I do group orders through the Super Saver club with my flying buddies so we're always in that 20% ($50 off $250 or $60 off $300) discount range. We've ordered a fortune's worth of hobby goods this year so far.

For August 2010, you can use 010B1 through 010B7 to hit various discounts, but you have to be a Super Saver Club member. With the Super Saver Club costing $10, it's not a bad idea.