With the two infants I was unable to breastfeed, I used Similac Soy Isomil and Carnation formula. The shelf life was adequate for both, and they both met FDA requirements. While Carnation, I feel, smells better and is easier for infants' digestive track, Isomil was recommended for one of my daughters when she proved to be allergic to breast milk.
I noticed someone mentioned the La Leche Society. In my opinion, this organization is best to avoid as, in my experience, some of these people are very unwilling to understand some infants are allergic to milk and that some women are unable to produce milk. If you wish to breastfeed, goddess bless you! But don't feel pressured into doing anything that might prove unhealthy for you or your infant. I wish you the best of luck for you and your baby :)