I don't think you will find any source online where you could get butts shipped to you at a total price of meat plus shipping for $2-3 per lb. The shipping costs are the killer every time.
I take it you don't have a Sam's close by. Won't a local supermarket get them in for you? Talk to the meat dept. manager. You might have to buy a case at a time but get yourself a dedicated deep freeze and freeze what you don't need this time.