I have actually built a homemade system that consists of a Rubbermaid cooler that has been sitting in the garage, a $10 hair dryer from WallyWorld and a Dayton t-stat from the office salvage bin. I have the stat set to 115 deg. and the hair dryer cycles on-off every 45 mins. or so. It only runs for about 10-15 seconds at a time and keeps the cooler nice and warm. I have added some 100 gram desiccant packs I purchased on EBay really cheap. I'm going to design an interior mounting system for all of the components and post some shots when complete. After keeping in the cooler for a few days I'll put the rolls of filament in LARGE Ziplock with extra 100 gram desiccant packs for storage. I plan to make some trays for pellets once the interior is complete. I'm sure an oven would be better but I can't get one in the lab. I'm looking for a better stat that can support a higher temp. I know Grainger carries the exact one I want, for about $120, but I'm building this out of basically discarded parts with the exception of the hair dryer and desiccant.
If you build it they will come. Then they will make fun of it, tell you it's not worth doing and go home and try to copy you.
If a picture is worth a thousand words then being there is worth a thousand pictures.
(2) Stock Makerbot Z18s, Filastruder w/Melt Filter, Filawinder, Autodesk Inventor Design Suite 2014 .........so far.