Use the websearch option on your provider (google, yahoo, etc.) . Type in the particular wood you are interested in and do a web search. There are quite a few different sellers that have good woods. Some will have minimum orders, which may limit your options. One of the sellers I buy from has a 10 board foot minimum on exotics and a 20 board foot minimum on domestics. If you are just looking for a few blanks, that can run into more money than some want to spend.
If you are looking for just a blank or two, try ebay.
After 9 years of callmaking, I still do a websearch here and there to find new suppliers. One that I had used for several years went to a minimum 100 board foot order requirement. Needless to say, I won't be ordering from them again.