I tend to watch RCU and ebay for deals. I buy kits that look like good prices and that I am interested in. Have about 50 right now. If I want one and am short, I can always sell another that I would never build that I got a good price on. Not a bad way to do it. Then youl always have something to build. The only problem is when you get bored with the one you are working on and start another, then end up with 4 going. You have to stop and complete one at a time till they are done at that point.