If you're interested in university-style courses but don't want to commit to a degree, you can take specific subjects or short courses online. While these generally aren't free, you won't be racking up debt with student loans.
The Great Courses
University-level short courses from professors and lecturers around the world across a range of topics. Most have around two dozen half-hour seminars – ideal if you don't have big chunks of time set aside to study.
Cost: Pricing options vary
Choose between video download or receiving a DVD. Some courses offer a lower price for audio-only, and most come with a guidebook. You can often pick up audiobook versions of The Great Courses at audible.com at a considerable discount, minus the course guidebook.
Categories are split into science, history, fine arts, economics, literature, philosophy, religion, mathematics, high school, better living and professional, with 25 to 200 courses in each.
Founded by Harvard University and the Massachusetts Institute of Technology (MIT), edX now has more than 120 institutional partners, including Berkley (California), Oxford (UK), Princeton (New Jersey), the Australian National University and the University of Adelaide.
Cost: Most courses are free
Most courses are free and let you learn at your own pace, giving a rough indication of how long it will take, as well as a difficulty level. These free courses also offer a paid, verified version, which includes graded assessments and a certificate from the university.
Other courses are paid-only and include assignments, regular group discussions, instructor feedback and live video chats. Similar to a real university course, they follow a stricter schedule.
Coursera's online courses are created and run by educational institutions, with options to undertake full business degrees – with associated costs and full-time study requirements.
Cost: $US29–99 for a short certificate course; $US39–79 per month for a specialisation course.
There's also a seven-day free trial so you can dip your toe in.
There are also professional resources from companies such as PWC, Goldman Sachs, Intel, and IBM.
Partners include the University of NSW (UNSW), University of Sydney, Macquarie University and University of Melbourne, as well as overseas institutions such as Yale, Princeton and University of London – 145 in total.
Courses come in themed sets called specialisations with coursework including hands-on projects and real instructors, culminating in a certificate of completion. Some specialised courses take a few dozen hours while others can take months of 10 hours or more per week.
Skills to boost your career
There are plenty of non-academic websites that include professional development services. If you want to improve your current skills, or are planning on moving into a new line of work, this can be a good way to get started.
Lynda.com is one of the biggest names in professional development.
Cost: Around $30 a month; plus there's a one month free trial.
Courses range from the broad – such as marketing basics – to the more specific, like how to conduct business-to-business marketing on social media platform LinkedIn.
There are thousands of short courses and over a hundred categories, often around five hours in length (but this can vary), with video tutorials, transcripts and exercise files you can download.
Claiming the largest selection of courses in the world (more than 80,000), Udemy relies on its users to create content to sell for their own profit, using tools provided by the website.
Cost: From around $20 to $200 a course with lots of free options too
Topic categories include web development, design, business, IT and software, personal development, marketing, music, and photography.
Courses can include over 40 hours of video, dozens of articles, and downloadable resources, as well as a certificate of completion. However, not all their courses are so generous – some have just one written article, few downloadable resources and less video content.
Mentored by masters
It's easy to forget that many celebrities are famous for being really good at what they do. This is the philosophy behind MasterClass.
Cost: $140/single class; $280/annual subscription
You can learn chef skills from Gordon Ramsay (without the swearing), acting from Helen Mirren or Samuel L. Jackson, writing from James Patterson or Margaret Atwood, jazz from Herbie Hancock, conservation from Dr Jane Goodall, and chess from once-undisputed world champion, Garry Kasparov.
Other topics include editing and writing for film, singing, design and architecture, tennis, comedy, business skills, fashion design, performing arts and even space exploration by ex-international space station commander, Chris Hadfield.
Each personality has created their own course of video lessons, usually between 20 or 30 videos apiece. Upload your own video using what you've learned and you may even get personal feedback from the teacher.
Courses can be taken and paid for individually, or you can pay $280 for an all-access annual pass.
Learning a language doesn't have to mean night school and regular weekly commitments any more. Free websites like Duolingo and Babbel offer more than just videos; they have interactive exercises that increase in difficulty as you learn at your own pace.
There are more than 30 languages to choose from, some of which have millions of active learners. There's even a course in Klingon, the fictional language from Star Trek, which has more active learners than nine other real languages.
Cost: Free, or pay a subscription for no ads
Courses are created by community contributors who work together to build a polished product with in-depth exercises ranging from basic to advanced. Language lessons incorporate reading, writing, listening and speaking exercises – utilising voice-recognition software.
If you find something tricky, there are user-generated comments for each section that can help.
Duolingo is free on PC web browsers or available as an app on iPhone or Android. The apps come with ads, but you can pay a subscription ($14.49 for one month, $65.99 for six months, and $109.99 for 12 months) to geo ad-free and also gain offline access to lessons. The web browser version has no ads.
Want to be quickly conversational in a new tongue? Babbel has fourteen languages to choose from: German, Spanish, French, Italian, Portuguese, Swedish, Turkish, Dutch, Polish, Indonesian, Russian, Danish, Norwegian and English.
Cost: From $10 a month
The focus on conversational language can help if you're brushing up for an overseas trip.
There are also specific segments on pronunciation, or the more unique or quirky elements of each language's grammar (from an English-speaker's perspective).
Want to learn an instrument? Services range from interactive phone and tablet apps to places where you can get live video lessons from a real human tutor.
Live Music Tutor
Create an account, pick an instrument – from accordion to xylophone – and search for a professional tutor.
Cost: From $35 a lesson for kids
Individual sessions start at about $49 per lesson for beginners, up to $83 for advanced. Children aged 3–12 pay just $35.
There are also group lessons at all difficulty levels, which go for 60 minutes for $25 per student.
Learn over live video chat with professional instructors (webcam required), but this is a global service, so some time zone finagling may be required.
Yousician is an app for learning guitar, bass, ukulele, piano and singing.
Cost: Free and subscription (starting at $150/6 months)
Choose a tune and play along on your instrument (you can even upload your own songs). The app listens to you play and gives feedback on accuracy and timing, along with historical statistics on your progress.
There are also expert-designed courses that let you choose between learning different styles, such as rhythm or lead guitar. The difficulty level extends from complete beginner to professional.
The free version limits lessons to 10 minutes per session. The premium subscription allows unlimited play time with access to guided lessons
If you like the idea of making something with your own hands, you can pick up courses on woodworking, sewing, carving, pottery and more. You can also find quick guides for fixing things around the house or making small improvements.
Experts and enthusiasts share their knowledge on anything from specific, one-time projects to the fundamentals of certain skill sets.
Cost: Around $30 a class or $3/month for subscription
Class categories include 3D printing, CNC (computer numerical control), electronics, workshop, sewing, craft, food and design. There's also a kids' section to entertain younger members, and some classes are free.
And there are lots of do-it-yourself projects, such as how to make your own adjustable-height table using a car jack, building a basic toy robot, binding your own book, or making an acoustic guitar from scratch.
More about life hacks and guides than lengthy courses, this website focuses on short-term projects such as weaving your own basket, making a yo-yo, or crocheting a personalised baby blanket.
There are also some general knowledge resources, such as how to identify old glassware when antique shopping, cleaning tips, and advice for different painting styles.
Instructions are often not as detailed as they are on Instructables, nor do they have as many visual aids. They are free, however, and it's easy to browse specific categories in search of a project that catches your eye.