Another approach and the route I went is to go for the nano turibnes. The engine still costs the same as a big one but the airframe will be dramaticly cheaper and your 500ft runway will be very good.
The Venom setup with a 4.2lb thrust Lambert Kolibri T15 would cost you about $2700, it will provide flying opportunities at any airfield any time, so alot of true usable fun for the money. This kind of airplane will also provide a relaxed feeling when flying as the airframe is so inexpensive and a single big EPO bumper to protect the turbine if you crash.
At first glance buying a small turbine sounds wrong, but thinking about it it makes more and more sense