Online photo printing shops seem to have the most confusing pricing schemes imaginable. So I recently ran a quick comparison of a bunch of different vendors to find the best prices for a given number of prints. In terms of cost there are really 3 front runners, clark, pephoto and photocheap. I have not ordered from any of these so I can’t speak for quality or ease of use of interface. But a quick summary.
More than 105 prints, use pephoto
between 66 and 105 pephoto and clark are constantly trading back and forth for best price (every 10 prints or so).
1-65 clark (except 6-10)
So I’m probably going to use pephoto for anything more than 100 prints and clark for anything less (just to only have to deal with two interfaces). Additionally the cost difference when they’re trading back and forth is minimal.