Personally I wouldn't. 24 tokens is a lot to spend if you are on a small budget like you are. We are only 9 days until the next season, so unless you are tanking you are going to be left with a 3 star (albeit fast player) pretty soon.

I'd rather use the tokens on buying a 5 star player in 9 days time off the auction. He will be a slower trainer more than likely, but he will be a lot better quality wise, with possibly being a lot cheaper to sign too.

Up to you however, others find good value in signing academy players. Personally I haven't ever bothered keeping them.