Its not really the stove or the coal. Its the size of the home, how hard to heat, etc. (user knowledge too) BTU's are BTU's.... wish member Isayre was still posting with his calculator mind, but if you have been using other fuel sources you can figure out how many BTU's of fuel you need to heat your home. Click on the coalpail.com link in upper left corner and then click on fuel comparison calculator. You can twist the numbers, cost and efficiencies to help get an idea.
Not many coal or wood stoves have the efficiencies they claim. Use 60-70% efficiency to compare to other sources and its close enough. Saving 1 or 2 pounds of coal a day doesnt add up to much savings over 6 months so add simplicity into your figuring.
Trucking costs are starting to go crazy. Ant might be affordable now but I wouldnt count on it in the future. There might still be some way to burn what you have there without smoking yourself out. Larger sized coal is one of them. Exhaust fans another. Maybe others