Wasn't sure whether this was worth a deal post, as it is just a link to a site, but a very handy one. I'll pop it in misc for now.
If you buy anything from amazon, they have their policy that if the price lowers within 30 days of delivery, they will refund the difference. You have to be the one to instigate the refund, so it is up to you to watch out for price drops. TimberFrog has created a tool which emails you whenever there is a price drop, see it here:http://www.timberfrog.com/apcn/
You just put in the link to the item, I set the change to "any value" and pop in your email address. I changed it to "any new price", as amazon don't give you a refund if it is from a marketplace seller.
Useful tool I think!!