So this is a topic which is very near and dear to me. I was dropping almost $18 for a 20lb bag of pellets which lasted me 1 - 2 weeks MAX when the wife said to me it may be time to reconsider your $1200 purchase of the Rec Tec.
I have done my research up and down and have contacted a few of the companies that produce pellets for heating purposes. The first company I reached out to is Greene Team which is usually stocked by Lowes in my area. I actually called on two separate occasions and spoke with two different representatives and received the same answer. They explained to me that their pellets are 100% hardwood pellets with no glues or other toxins used as binding agents or fillers. The only difference between this and and the pellets that you pay $15 - $20 for a 20lb bag is the saw dust from the mills are not specific to a certain type of wood. So you may get a mix of oak and maple and poplar in your pellets. He confirmed that he personally uses these pellets in his cooker at home and feeds all the food to his children without any hesitation. The reps knew I was not a big pellet consumer and really had nothing to gain from me besides my $50 every 6 - 8 months. Because they knew I didn't heat my home with pellet fuel and I wasn't their average customer buying a ton of pellets at a time.
So I picked up 5 40lb bags at my local Lowes this past spring and burned through them all summer and I have concluded that I am 100% satisfied in the wood flavor in all of my cooking. Which includes high heat and low heat for smoking. Even in my baking we are 100% pleased. My only gripe (and it's not even a gripe because of the massive savings benefits) is that it burns through these pellets a little bit faster. My friends and family are more than pleased with the cooker and what it produces.
So all in all I say do your research and if you can confirm that you are getting quality 100% hardwood pellets with a reputable company I say paying $6 for a 40lb bag of pellets is a no-brainier!
Please shoot me a PM if you care to discuss more, I love pellet talk.