In general, at home filament extrusion is in its infancey, and there is a learning curve similar to learning how to build/use a reprap/ 3Dprinter. That being said once you figure out what your doing, you can make spool after spool of quality filament for $8/kg for ABS and around $12/kg for PLA. Having your own extruder also allows you to control what goes into to your filament. No more worrying about cloging your hotend (as long as you have a filter installed in the extruder) You also have a high degree over control of colors. Also, you can make whatever diamenter you need (1.75mm or 2.85mm). Your not limited to PLA or ABS either. I have extruded PP, PC, Nylon, TPE, TPU, and Acrylic, but I do not know if the UM2 can handle PC. You can see some of my work with the Filastruder at this link:http://www.soliforum.com/forum/23/diy-filament-materials/. The cost of pelltets for experimaental materials is cheap too. I want to try some of color fabs pellets, but with the purchase of my UM2 I need to be a bit more frugal.