I have some questions about shotgun ammunition?

walmart will be the lease expensive ammo. your 12ga can be used to hunt any animal in north america with the proper ammo and with in reasonable range ,thats why they make different shot sizes and slugs! the effective range is about 50yrds, a little farther with slugs. for dove/quail # 8shot, rabbit/squirrel # 6shot, goose/fox #2shot, deer buckshot/slugs,slugs for anything bigger than a deer, just to give you a basis of which shot for an animal size! hope i didnt confuse you and this helps! happy hunting! make sure to have all licenses/tag/stamps/safety courses before hunting!