Posted By:
fkwBest % profit
About 2 years ago, In the minor league card category (great place for finds), I won a card for $1 (1949 Sunbeam Stockton Ports Sandel) with $2 shipping the total was $3, I sold it within 2 weeks for $175 (58X more than I paid for it, including shipping).
A few years ago in the memorabilia category, I won a postcard for $40 (Ullman C.Mathewson), sold it for close to $2K (about 50X more than I paid)
Those are my best 2 deals as far as the difference between buy and sell prices.