This article is from the Radio Control (R/C) Flying FAQ, by Shamim Mohamed firstname.lastname@example.org with numerous contributions by others.
>What kind of cost am I looking at for a solid training glider or
>powered plane, with all gear?
$200 is in the ballpark. $120 for a 4-ch radio, $60 for a 2m glider,
covering and other supplies. ARF Gliders---$100 + radio + supplies.
Powered planes: about $350-400---$120 radio, $70 plane, $120 engine + supplies.
(By "supplies," I mean things like rulers, knives etc.)