Renting a stump grinder isn't exactly cheap either.
They wanted $100 for 4 hours of use here.
You could burn it with charcoal, as long as it isn't green, then take a axe to what is left (which isn't much), though, that isn't always a option for some areas, and since your playing with fire, safety first.
Copper nails also work, though you need like 30-40 of them for a good size stump, cover stump in a plastic bag, then about ..6months - year it will be really easy to get rid of what is left.
Another option is to use it as part of your landscape. They make nice stools... or have the kids paint designs on them to scare things away (ha!).