I have ordered from Create-for-less.com -- sometimes it seems like they have random things but I have found things really cheap there.
Etsy suppliers are also a good source plus you are supporting the team!
When I started, I started searching on line for wholesale supplies that I knew I needed. I kept a list of each vendor, and started comparing prices. I actually kept a spreadsheet (but I'm crazy like that) anyway, that helped me decide where on line I would get my supplies.
It has helped to keep my costs as low as possible, and I still compare shop ;D
Good Luck!!