RE: Does it cost more to by an ARF or to build from scratch
OK. Then it depends entirely on how much you value your time, and whether you consider time spent building a gain or a loss.
If you pay yourself minimum wage you cannot kit for less than an ARF. (IMHO)
But you can definately build a better plane (wood, integrity and component quality) than most ARFs; though there are top quality ARFs for those willing to pay.