Depends on how big (data) each picture is and how many you plan to take. Storage is stupid cheap on SD cards, I'm guessing a 16GB is about 200x the data you will need, and they're only $10-$15.
Some cameras have a limit on how big of card they can take. My old Cuddyback the limit was 2. My older Bushnell was 4 and I think my new Bushnell that I have ordered is 32 or maybe a 64. You might want to see if it says on your instructions. I ended up picking up my cards at Costco,
Just watch where you place it and listen to the guys here who have used them. Branches bumped by the wind can give you pics of nada (I now know). Try doing a search on game cams, here?