A Start for a 10 year old
Well for a "cheap" first plane would probably be a fighterbird or firebird xl. Both of them are $130 and under and a perfect first RTF park flyer. Their 2 channel (left/right, throttle makes you go up and down) so with out the elevator channel it teaches you to fly close so when you battery dies you wont land a mile away and will teach you how to set up your approach.