RE: beginner plane purchase logic
General rule of thumb is to take the kit cost and double it allow for the cost of covering, glue, and misc. parts required to finish it.
Cost of engines and radios don't apply, since that depends on what you have on hand.
Cost of tools? You can build with a single edge razor blade, household iron and a couple of popsicle sticks, but man up. Men buy tools their entire life. It's in our DNA.