I've collected hack saw blades and a little hobby saw. Saw blades have a variety of tooth arrangements. Wooden Clothes pegs. Buy an entire pack of wooden clothes pegs. These can be joined, cut and redesigned to produce clips that help hold different model parts.
Kits are available virtually at any hobby, toy or major shopping store.
The problem is that not everyone stocks the same kits. Most major shopping stores, stock cars and aircraft, and then only a small amount of each. Toy Stores usually have a larger collection with a bit more variety. Hobby Stores have a larger collection of kits, but most stores only stock popular lines, Armour, Aircraft, Ships, Sci Fi, etc. If you are after kits that are more exotic, you may have to visit a specialist store.