every LBS scrap bin will have lots of washers in it. However there are problems;
- 200 is still a lot
- the washers are usually (but not always) steel (convex part) and aluminium ( concave part)
- washers vary in thickness; not only are there thick and thin ones but they vary between manufacturers
so depending on what you are trying to do exactly you may be better off with something from a fastener suppliers.
FWIW you can accommodate misalignment between parts by using squashy (eg rubber) washers, provided the service loading of the bolt is not excessive. It is also possible to use a short spacer sleeve, washers, and a rubber grommet to provide a fixing where the bolt can be fully tightened and yet the part can articulate slightly.
cheers