When you say "stove coal" do you mean the large chunks of coal that go in a stove, as opposed to "nut coal" (medium chunks) or "pea coal" (small pieces)? Or do you just mean "coal to put in the stove"? Make sure you use the right terminology when you place an order, because you are likely to get what you ask for.
Regardless, you mentioned the restriction of not lifting more than 25 pounds. Maybe you could buy 50-pound bags and hire a high-school kid to come in every week or two and fill your smaller buckets. (Good luck finding a high school kid that wants to work.
). Incidentally, a two-foot length of 6-inch stovepipe holds between 21 and 25 pounds. That's what I use to carry in my coal and feed the stove. I don't know how much a 5-gallon pail full of coal weighs, but I would guess more than 25 pounds.