You 100% correct the total budget on this engine is 60$ I picked mine up on ebay it was 39.95 including shipping I'm pretty sure there is a method to their madness and the engines I find on eBay for under $60 are ones that failed the quality control inspection which I will be getting into soon none the less with 20$ you can definitely get some key crucial parts to make these little motors scream maybe a rocket key ( I will be making my own) a velocity stack and air filter and a premium spark plug will see how things go as my build progresses.Budget builds are most likely on everybody's mind. The real question is what did you buy this engine for originally?
You can blow most of your budget just on the purchase. I understand that you're basically just cleaning up and balancing the motor. With just labor and time and no other parys incolved.
You could buy one of these motors for $100 not put any money into it or sometimes you can pick these motors up for $40 and you're in the golden Zone for anything you want to do, no other parts or replace some very important items.