RE: Stocking up on balsa
Only 6 miles to the LHS, you lucky stiff!! Being 6 miles away you need to have absolutely nothing on hand, unless this seems important to you. Like BBBair & Test005 state, after a kit or two you will have a sufficient pile of balsa, ply, spruce & bass sticks to last the next 5 years. Notice I did say "KITS" If you're talking ARFs, then you may actually need to buy some stock. However, I would wait until I know what it is I need, before buying. Even if building from plans, you still really can't plan ahead what should be in your inventory.
Organization is important and saving fuel is a worthwhile and a noble endeavor! I always keep a paper list of items I need, so when I go to the Hobby Shop, I don't forget what I need to pick-up. Now, if I could just keep from going there, simply because I want to!