Your best bargain will be Walmart. As for the particulars of what ammo, in my area it's either the Federal Champion or the Remington UMC. Both will produce very good accuracy and are quite clean shooting. I'd recomend that you try to avoid the Winchester White Box, my experience with this ammo is that it is extremely dirty shooting and will double the time involved in a good cleaning. I'll shoot the WWB if I can't find anything else but I would prefer not to.