Corsair XMS2 Xtreme Performance 4GB (2 x 2GB) PC6400 DDR2 Memory for $14.99 shipped after this $30 rebate. Note that orders need to be placed by 3/5 for the rebate to be valid. Most places have this set of RAM kit for $50 or more.
Originally posted earlier, this deal has been revised and this is a friendly reminder.