there's a group online called "freecycle.org" You can't sell or buy there it's giveaway. Every major town in the us has a chapter. Now and again someone has a wornout piano to give away. Spectacular source of nipplepick wire!!! I found a 1/4 carat diamond under the keyboard along with a bunch of indianhead pennies and a 1903 dime...perfect condition. Some of the really old ones have real ivory and ebony keys. Shoot...ya'll know I'm cheap.
Craft stores that sell a lot of floral supplies sell bundles of 4 inch tying wires in different sizes for about a dollar. enough to make hundreds of picks.