I use Fluker's to buy my crickets. I've used several companies and they're far and away the best. They're located in Louisiana and I'm all the way over in Washington and they get here promptly, alive and kicking, for a reasonable price. While I haven't had an issue, I'm told by other customers that should a box show up dead they replace it without much trouble, usually with a good overcount!
The only one I will caution you about is LLLreptiles- I had a horrible experience that resulted in 2000 dead crickets that they refused to replace or refund. For some reason they use a shipping company that only ships in CA, so it took over a week to get here and then they left it in the snow!
Poster is owned by Tristan (human- 16 months) four dragons- Gibby (9ish), Dora (4), Miss Priss (2) and Inara(1 year!) and one albino mocha fat-tailed gecko, Lizzy (4).