For a decent electric charger for a commy it will cost a lot more than $50. It'll cost hundreds and wont make a noticable difference. You can combine several of the highest powered chargers and it will give you a gain but it is a very uneconomic way to get power in the end.
Modifying a car is all about trial and error, if he's insistant then let him spend his money on one and see that it is rubbish for himself. There are no miracle gadgets on ebay. I reckon everyone on here has tried something at some stage from ebay that sounded too good to be true and was.
If you dont have money then dont try to buy modifications. Just keep it simple. Look at your engine bay and ask yourself how can I get air in and out of this thing quicker also how can I keep it cooler... Without spending money. Look for small things that you can make yourself. You might also find some excess weight that can be removed throughout the car (this is vital).