I buy all of my reloading supplies in bulk as well. I am fortunate to get all of my components from Oregon. The shot is new and I buy 8# kegs of powder. I reload for between $3.00 to $3.50 for shells equal to a AA or STS.
My loads are 1 oz #7.5 or #8, Cheddite primers, Downrange wad, gun club or STS hull, and 18 grains of Hodgdon clays. I load on a MEC 9000 progressive and can get a flat done in a little over an hour. If you don't buy in bulk, it may not be worth it to reload.