How can I turn sandy lot into a wild flower meadow without bankruptcy?

We bought a house last summer on a nature reservoir with lots of pine trees and oaks on it. Part of the yard is very sandy (as it's understandable with pine trees), but I'd love to turn that into a wild flower meadow now, since it's way too sandy and boring and nothing seems to grow on it normally. Last fall I started dumbing all the fallen leaves on it in order to try to enrich the soil at least a bit, but don't know if I'm really just wasting my time with that...? Is there anything I could try myself instead of hiring a professional to deliver tons of topsoil and God knows what? Would dearly appreciate any advice! :) ♡