You should edit your current offer into the original post to save others' time.

I don't have a giftable Civ 5, so 4 BTC is the best I can do without losing money.  The 3 BTC offer is probably from someone who bought it during a sale.  Realistically, if you want it now you're going to have to expect to pay more.  If you don't need it now, then just wait for another sale and ask then.  I'm sure you'll get better offers.