I've been called a mercenary before, but the only reason I spend time working on software development "hobby projects" is with the sole aim of learning new skills that will make me more money on my job/contract work or at least keep me up to date with my skills. For that reason alone, I use AWS for side projects. Companies pay well for "AWS Architects". If I want to do a hobby project and save money, I could just as easily set up my own server and use my own gigabit home internet.