Cheap ammunition for BB
Cheap ammunition for BB guns is relatively easy to find. Manufacturers sell the pellets in bulk so you can usually get a good price on a set of a few thousand. Cheap ammunition can be found online or in sporting goods stores. BB guns take metal ammo (lead, steel, copper), while airsoft BB guns use plastic pellets. Make sure you pick the right ones for your weapon, and never re-use the metal kinds!
One can usually purchase cheap ammunition for the average price of about $.01 a pellet. If you are paying more than that, you need to look harder. BB guns are not as expensive to keep loaded as a paintball gun, which is part of the reason more and more war gamers are making the switch to airsoft. Ammo can be bought cheaper and even re-used. Win-win!
Different kinds of cheap ammunition for BB guns
In traditional BB guns that shoot metal pellets, you are not supposed to shoot the same round twice (even if it appears to the naked eye to be in perfect shape). Minor scrapes and nicks always occur with each firing. This can lead to hazardous situations because your shot may not be accurate. It's also more expensive in the long run, because it can quickly ruin the rifling inside your airgun's barrel.
When you buy cheap ammunition, make sure you also purchase an easy-pour funnel or speed loader, which are very inexpensive. BB guns are notoriously hard to load without them. The magazines can overflow, the pellets can spill and be ruined with mud or dirt, or they might roll off and end up under your bed. Invest in this ingenious little device and save money in the long run by not spilling your ammo.