I have made a few purchases (food, chillers, sticks, willow toys) from members on this forum and have had no trouble. You just need to do your due diligence before you make the purchase. I stick with people that are frequent posters to start with, then look for any threads related to that seller.
With shipping, I paid about $1 a pound less for Mazuri, including shipping costs, than I would have at the local Petsmart. And that's not counting the $8-$10 in gas that I saved shopping with my fingers and the in-stock guarantee.