As a return of investment, I've seen some people being able to sell crappy html5 games (crappy, really, they were made during the flappy bird incident IIRC) for something around 400 or 500$ to publishers (or even an automatic 200$ to fgl which helped distribute them afterwards if you've implemented their C2 API but that changed too) so I guess it is pretty much a win win situation (though the situation for that particular case changed), however it really depends on what you want to do in the end, you want to do android only games? I would say this is not what the product has been designed for (it is doable as some people can witness), and 100$ investment is not that big (if you are planing of making money out of it, you should target more than that), but be wary of everything before buying it, if your expectations is to make a return of investment, you should be able too without much issues.
PS: I will not describe any money making process in any way, as I am not an expert, I made my money back but did not wanted to earn more money afterwards so I stopped If you wondered.
PS2: The free edition can get you started to try doing things to see if it corresponds you (you cannot make money out of it sure, but at least you will know a little more if it is worth your time);