Breastfeeding purchase question

LCLaw3

So I plan on going to pick up my breast pump this week at a store designated for lactation, etc., but when I went to other stores like Target and Babies R Us, theres tons of "accessories" so to speak...like cream, pads, freezing bottles, etc.  I was just wondering if anyone who has breast fed before or knows more about this can tell me what it is that I need exactly and how much of it.  I don't want to buy things unnecessarily, but I want to bring what I need to the hospital so the nurses can teach me how to use it all.  Thanks!