I roll my own. Golden sabers from midway, brass from the range, powder and primers from Indiana Gun Club. There is no cheaper than that for jacketed .380. The cheapest .380 for me is a cast 102gr over some titegroup. I don't remember the recipe offhand, but it's less than 2.5 gr.......
I know this doesn't exactly answer your question, but if you want the cheapest, most accurate ammo possible, you have to make it yourself...