I'm in the process of building one myself. It's really pretty easy, especially compared to an AK rivet build. Anyway, I'm building a RRA 16 inch varmint. I did a spreadsheet and compared building one from just the parts, putting together a upper and lower, or buying a complete rifle. I found that with the prices I was able to get the items at, putting together a upper and lower gave me the most bang for my buck. I can save $150 compared to simply purchasing the rifle. With that said, I also priced various parts for a lightweight flat top and found that if you aren't after a specific brand and are flexible on the components, you can build one for much less than an off the rack purchase. For what I wanted to build and the fact that I'm not in a hurry, putting it together myself just made the most sense.