ORIGINAL: bigedmustafa
A .40-sized glow engine like the Super Tigre G-40 will cost you about $49.99. An equivelant brushless electric power system can be purchased to fly the plane with similar authority, it will set you back about $250 to $300 for motor, speed controller (ESC), and LiPo battery.
If you need to go cheap, go glow. If you need to go electric, spend a little bit extra and buy a real airframe. Balsa flies better. You can purchase a Ready-to-Fly electric trainer with a brushless power system and radio for around $299.99 plus batteries:
http://www.hobbico.com/airplanes/hcaa12.html
Good luck and good shopping.
Another cost often overlooked with electrics is the recharger capable of handling the flight batteries. 'Taint cheap and usually runs about as much as a well equipped field box for glow engine models.