It depends where you live, but I've found that ebay is a reasonable place to look, but I'd certainly not bid without having seen the car. If I was in the market for a project spitfire I'd be looking at https://www.ebay.co.uk/itm/166706064301 in Basildon (Essex). 10 day auction, 5 days left, £400, 7 bidders, reserve not met.
Looks like a fair amount of work but worh rescuing. If the reserve is not met it's maybe time to barter. I bought an alfa romeo that way (agreeing a 'buy it now' price to keep it on ebay) after meeting the seller after the auction ended. At your age, you are certainly likely to find a sympathetic seller!
Good luck, and please let us know what you buy and keep us informed of your progress. Lots of helpful experts on this forum.