Moms who are not BFing or pumping

How many of what size bottles do I need ?

Someone told me the hospital will give me a couple servings of formula but what should I buy to start out? A small can of regular ? And a small can of sensitive in case he can't do the regular ? I don't want to go to the store for a new can of formula every two days(unless literally absolutely necessary). What's the best route to go with this ? Also how much will he eat at a time ? First week ? 2nd week? How long should a small can or big can last me (as long as his tummy handles it ) in the first month?