there's a coupon that will take $10 off a $30 total, to use it you need a credit card that you haven't used at buy.com yet, so idiotic buy.com stores every single credit card number you ever used with them, which is a huge security risk, if you want to use a coupon for "new" customers, buy.com will check the credit card number you entered with any existing ones in their database, if there's no match, you can use the coupon...
somebody should crack buy.com over the head with this questionable practice,