Hobby shops-brick and otherwise, can be expensive sources for common stuff. In my infinite stingyness I've found a few cheaper or free alternatives:
Dept. stores: emery boards, tweezers and cosmetic brushes (for dusting or pastels)-guys, pls avoid the lipstick and mascara.
Hardware stores: Bulk thinner, cleaner, sandpaper, windex (for clean-up after acrylics) and tack cloths.
Fast food: Plastic straws (for holding parts while spraying) and those little condiment cups for mixing epoxy. Plastic knives for putty.
Grocery stores: Plastic and paper plates for mixing and holding parts. Paper towels and Future of course! Small Pyrex bowls for decals.
Hope this saves you enough to buy more models!