But I'm not sure how to prove myself so that someone will take my offer. I am willing to trade gift cards in increments of $25 (14 BTC), $50 (30 BTC), $75 (40 BTC) or $100 (55 BTC).

I'm not too sure of the exact rates but these are close to a $2/1 exchange rate.

Let me know if you want to figure something out.