Another example of saving money on RC models: My Astro-Hog is being built from loaned plans/instructions and all the wood I've used so far, save the 4" wing sheeting, was from my "leftover" stash. I ordered the taildragger landing gear from Sig when a past order was sent in and am carving my own headrest piece from a leftover block of balsa. The "cost" of this model is minimal though the fun I'm having is priceless IMHO.

Save all those bits and pieces. I use three leftover kit boxes: one for leftover sheet stock, one for misc. small pieces of all types and leftover stick wood, and one for misc plywood pieces and basswood/etc. This is in addition to my balsa/plywood stash. I've found I can very often find the right size piece of wood for various plan parts from the leftover stuff and thereby do not have to cut up a good sheet until I really need it.