Most cities have their own bead stores but since I'm in Brooklyn, these are my go tos. The selection at these places are great and suit both professionals and weekend warrior crafters. These stores can be a little pricy but they often have sales and the quality is totally worth it.
New York City:
Purl Soho - has a great selection of nylon Chinese knotting cord.
Everywhere (and for cheap):
Michael's - This is like the McDonalds of craft stores
Your closet- I'm sure you have old jewelry you no longer wear. Break it apart and make something new. See my upcycled jewelry for inspiration.
Someone else's closet- someone you know has jewelry sadly sitting in a bauble box going unused. Psst...the 55 and older set have the best jewelry for upcycling.
Thrift store- some thrift stores sell bags full of jewelry for cheap. There can be a whole jewelry wardrobe made by you in that bag. Also there are separate pieces sold (usually at a counter).
The list goes on and on for craft supplies.
Please share any places