How much does it cost to deal with the old stump is still sitting in my yard?

Priced by stump diameter measured at grade, not by the height of the tree that used to be there, and often at a per-inch rate with a minimum charge. The drivers that actually move the number: gate width and equipment access to the backyard, rock or gravel embedded in the soil around the stump, how far beyond the stump you want surface roots chased, whether grindings are hauled away or spread on site, and utility lines in the root zone. Several stumps ground in one visit costs far less per stump than separate trips.