Hello, I'm a college student from the US. We have a local resale store called "Goodwill". You can buy RC toys (and other stuff) by the pound. The cost is like $0.70 cents per pound (+/- a pennie or two) The store has 100's of bins and they dump donated stuff in them. Then you walk around and dig for your treasure. I have purchased a few RC trucks and a tank for less than $1 USD each. So keep this in mind where you live as there might be a place like this in your town for you to scrounge cheap robot fodder.