Great for content consumption. Not so great for content creation, by which I mean development. I'm aware that you can create code online, but I wonder how many are writing serious code on their phones, or even tablets. And though I'm not one for gatekeeping, I have trouble calling you a "nerd" if all you needed was to stream some movies and music.
Looks very nice! My favourite has been codingground so far.
It can save to GitHub, Dropbox, Google Drive and OneDrive, it supports multiple files and live console interaction. Customizable editor looks too, they even auto-save.
As a negative touch, it can be highly fragmentes - Numpy, Scipy and Sympy are all available, but as seperate 'Languages', independently of Python, Python 3 and Python MySQL. Same with CCS3 and Bootstrap.
If you don't have access to a machine with a development environment set up, there are a few ways you can write programs via a web browser.
You could work on practice problems on sites like HackerRank or CodeWars. These sites feature problems of different difficulties but often focusing on key language features and knowledge of common data structures which can be really helpful for a beginner to pick up.
If you want to try examples from a text book or other educational source and just want a sandbox to write and compile/run, you can use sites like Coding Ground which provide online IDEs. Appropriate projects will depend on your level of knowledge. Calculators and simple text-based games are good for beginners because they focus on input/output, working with text, and basic control flow.
Beyond writing programs, I found it to be particularly useful when starting to try solving problems on paper when I didn't have access to a terminal. Try coming up with a solution in plain written English, then translate it into pseudocode, and finally write up a program in your language of choice (on paper) as best you can. The last step is really useful for testing your memory of syntax and function names.
You can do basic stuff in the browser.
http://www.tutorialspoint.com/codingground.htm
Regarding a more proper computer, you can program on a Raspberry Pi if you have the monitor and keyboard laying around. I'd recommend any cheap computer and a mainstream, popular Linux installation. Start learning the command line, Python, SQL, whatever. You only need heavier machines, in my opinion, if you're doing GPU programming (CUDA etc), game development, or something requiring a lot of horsepower. But to just get started with learning, you really do not need to spend serious money.