I try to pick up little lots of them from time to time on eBay. I never pay much for them, although one certainly can! I just buy the ones that I think will complement the pincushions that I make for my thread catchers. These little works of art are the perfect finish for items made from vintage-look fabrics.
This hexagon button is EXQUISITE!
And this tiny one looks pretty on a Dresden pincushion.
And another!
I keep my collection of twinkles in a little velvet draw-string bag. They jingle like gold coins. My own little tiny treasures! I love to open the bag, spread them out and choose just the right button to go on my pincushions. Like I said, it's the little things...