Emfamil, similac and Gerber sign up for, emfamil has sent me a ton of free formula (I'm only planning to supplement so I am pretty much set for a while), register for sure with babies r us and target for freebies. Also there is a website called freeflys.com I think for spelling, sign up with the website and there is a tab for baby/children freebies or samples to try.
Sign up on enfamil.com and recieve emails with coupons and they send u free samples sometimes. Similac is the same. And if u have a target nearby, sign up for a baby registry online and then go to the store to pick up a free baby bag, full of stuff like a free bottle, binki, laundry soap samples, and coupons. And alot more depending on your target. If I can think of more I will post again but my brain is being lazy right now lol