Baby companies give out a ton of free baby samples but only if they know you're out there and have a baby. If there's a company that makes a baby product you'd like to try, you should visit their website and register your information with them. This way when the baby companies decide to send out free baby samples, they'll automatically send one out to you.
Pampers Diapers and Huggies have a rewards program. They have unique one time use codes found inside the packages of diapers and some wipes. Save those and enter them on their websites (after making an account-when you sign up for pampers you will get 100 pts) When you have a certain amount of points, you can cash in for Free rewards. There are a ton of different items, and they change them too. When I reached 1,000 points I cashed out for a Dora Potty Seat for my youngest! Yay!