Woot! Woot! Best Buy gave me the 20% with no problems, and the cashier actually apologized for it taking so long to punch in the codes. I got Rune for $22 and AoEII for $10 (the latter after rebate).
OK, the questions--
1. It's a Best Buy rebate that prints out at the cash register.
2. The 20% off thread is nearly on top right now. Just search for "Best Buy" if you can't find it. But hurry, it expires today!
I printed my 20% coupon at 600 dpi and cut it out on the black border, so that it looked like a real coupon.
Regular price at BB for AoEII is $39.99, and for the expansion pack is $29.99.
Dig, if you have your receipt, BB will probably refund the difference.