i get mine from beanfarm.com. 3" is 1.90, 4" is 2.15, and 11" is 3.10. they also sell the extra metal connectors for crimping. shipping is fast as well.
I searched around for the best prices, and was between The Bean Farm and Reptile Basics, and I ended up going with Reptile Basics b/c I think their shipping charges were cheaper.