There's a 'How much is a card worth?' thread pinned in the General Trading Card Game section. I also put a link into my signature were you can find this thread. I'd so about 2$-3$ if you find a collector who'll buy it.
Also, there is no grade better than mint condition other than Gem Mint, and I would be VERY impressed if you had a Gem Mint card, as most cards out of a pack aren't even Gem Mint