Woodturners, Woodcraft B&M has Spectraply pen blanks 20 for $10, down from $30
Here's a link for reference:
They also have a grab bag of larger sizes on sale too, as you can see in the above link. If you've never used Spectraply before, it's different colors of wood laminated into blanks. I have turned spindles with them, and they turn out really cool.