...and buy stuff that is sold by them, not by the Marketplace or another retailer through Amazon, do you know about their 30 day price guarantee? If the price of whatever you buy drops within 30 days of your purchase, they will refund you the difference. I just saved an additional $3.00 on a game I bought ($5.00 overall - the price dropped $2.00 from the time I ordered it to the time they shipped it, and then it dropped more after that).
You can go to refundplease.com and register the item, and then they'll email you if the price drops, with step by step instructions on how to request your refund. It's so cool!