Seriously, if you buy any amount of stuff online that you could get from Amazon (and don't have some other ethical objection to buying from them), just get Prime. It's super-convenient and pays for itself several times over for me every year. The free instant video isn't bad either, the selection could be bigger but I see it as just an extra on top of the basic Prime delivery savings. Also, other people at your address can use the membership along with you so there's the potential to save even more on deliveries, plus there's the Kindle library, Prime Music etc. as well if they're any use to you.