I have owned two Harm
An (sorry I get sensitive about the wrong spelling of the brand name

) stoves over the course of 19 years. I still run my Invincible (19 years) and a P61A. As others have said, they will burn just about anything so you don't need to pay high prices for pellets if you don't want to. Unfortunately last years pellet shortage has led to higher than "normal" prices this year. HD, Lowes, and Tractor Supply all seem to have a good supply. I participate actively in the hearth.com "Pellet Mill" forum. A wealth of knowledge there.
A clarification from an earlier post...Green Team pellets are manufactured in Pennsylvania and are a great pellet, just too expensive for my taste. Green Supreme is a New England Wood pellet product based out of Jaffrey NH but with two other mills in NY.