The market for SPS compared to other corals is smaller as well, and with the requirements most of them need (especially Acropora)-very clean water, high flow and high light-they're not very conducive to retail settings. Not only that, but they're on the high end cost-wise as far as wholesale pricing goes (they're not usually marked up as much as you think) and many die in the store before being sold. Standard retail markup on a medium Acro colony would price them in the $80-120 range (3-4" colony).
I'll be bringing in some acros over the next few weeks as well, and I'll let you know when I have some to get rid of.