I've just finished my second kit. I really enjoy the building aspect of this hobby. Seems to me, the first kit will always be more expensive than an ARF because of all the equipment that must be purchased to properly complete the plane (there are some good lists of required materials earlier in this thread). My first kit was a BTE Venture 60. The price of just the kit was $150 (plans, wood, some hardware, etc.). I have no idea how much I spent to complete the plane, but after all the specialty equipment/tools required to do the job right, it was a nice chunk of change. However, my second plane (Sig Wonder) went much easier and cheaper. It was a $40 kit and I already had all the tools I needed. I had left over glue, blades and covering from my previous build. So it was probably equal to the cost of an equivalent ARF if not a little cheaper.

Plus, there is no price that can be put on the excitement of seeing these plane take off for the first time.