So recently Ellora's Cave stopped discounting prices to vendors, meaning that their usual mark-up would double the price of books sold through vendors. So from their website a book might be $4.45.
Now if you look at Ellora's Cave books on Omnilit or AllRomanceEbooks they are listed as being double-price ($8.90), then normal price "after rebate". Doesn't that seem like the worst of both worlds? You have to pay the full price and jump through hoops to get some of that money back (presumably in the hope that some of them won't bother)?
Meanwhile Amazon is listing the full doubled-price with a discount that splits the difference between normal and doubled price ($7.12). So the vendor's continue to dance around the issue--but EC is still getting their money, I bet.