I'm kinda in the same boat, just getting started and wondering how much to actually invest in all this. Since I don't pay for electric, it's a little easier, but I don't want to spent a fortune for a little experiment if it's not going to pan out.
Ya the whole getting a C for making a hamster charger is a little low. I used to make models of the solar system and get A's lol. Also tried to make a laser and test what would resist it best which didnt work quite as well