antonyall,

A SPAD (Simple plastic Airplane Design) can be built very inexpensively from found materials. You can use the motor and radio from one of your trainers and not risk the balsa airframe while you are learning. If you do a search here on SPAD you can find links to step by step instructions for building. The corrigated plastic used for the wings may not be available but if it is the only other thing you have to find is a piece of PVC square pipe.

Lack of funds can be overcome by inventiveness.

Good luck.