I installed a pellet insert and chimney liner in my home in December. 25' chimney liner + insulation kit ran me ~$500, and the steel pellet insert I got from craiglist for $270. I figured that a 6" diameter wood stove chimney liner with 1/2" insulation wrapping would be tough to jam down my 25' chimney. But the 4" diameter for pellet stoves would be simple. Boy was I wrong! Even with the smaller diameter, it was a serious struggle for two grown men to jam down the chimney. Me, jamming the liner down the chimney from the roof, and my father-in-law in the fireplace with a rope pulling it down. I have no great fear of heights, but being loose up on the roof, and using all my physical strength to stay balanced while twisting and shoving the 25' liner down... makes my palms sweat just thinking about it. In the end, I'm still alive and I saved a chunk of dough between craigslist and a little DIY attitude.
The pellet insert is a Lopi PI-400 FoxFire model, I believe manufactured sometime between 90-94. It's probably not the most efficient model, but it definitely warms up the house and creates decent ambiance. It doesn't have the same character as a wood, but it's definitely more user friendly. Filling up the hopper, and the flick of a switch and I have fire for 10 hrs with no need to tend.