What size baby diapers?

I am pregnant, and want to start buying some things. My mom said she would buy a pack of diapers every pay day and it helped them out a lot..so, that's what I want to do. I plan on breastfeeding, but is there any type of formula I should buy as a back up? I just want to start getting little things, so that when... show more I am pregnant, and want to start buying some things. My mom said she would buy a pack of diapers every pay day and it helped them out a lot..so, that's what I want to do. I plan on breastfeeding, but is there any type of formula I should buy as a back up? I just want to start getting little things, so that when I get further along I can focus on all of the big items. What size diapers should I be buying..I know that babies grow fast!
Update: Any other staple items I could start buying early on?
Update 2: Thanks everyone. So, I think I will just buy maybe one pack of each size..and just start with bath stuff, first aid, burp clothes, plain white onesies...and so on..I just feel the need to start buying stuff..haha...and I did see a cute black and white diaper bag..will have to get that too.....lol
12 answers 12