Another point
The issue of the retailer's profit margin is obviously an important point, and I'm sure that IPR has done what it can to make their service as profitable as possible to everyone involved. Don't forget...products "on sale" at IPR yield an even better profit for the store, especially since the store is free to set its own retail price (IPR says so).
But that's only one side of the polyhedron. Don't forget the purpose behind IPR: to give everyone's FLGS access to indie product...GOOD indie product...at rates that are at the very least COMPETITIVE with mainstream distribution. Again, this is product that cannot be obtained anywhere else for *retail* sale. Before this, your customers had to order directly from the creator, draining gaming dollars from the local economy...and that's a loss of business to your store.
IPR carries products that customers want. And they are offering a way to put them on retail shelves so that the retailer can still make a profit. As much as he would make on a Dungeon Masters Guide ordered from Alliance? Perhaps not. But a reasonable profit nonetheless (especially if you meet the free shipping requirement). And last time I checked, few FLGS were in the position to be able to say, "I know you want this product...I even have an indie distributor that I could get it from. But the lower profit margin of 25-35%, after shipping costs, means that it's really not worth my time. And that means YOU dear customer are not worth my time."
Good business sense would dictate not ignoring an avenue of obtaining new, creative, high-quality products. If nothing else, you owe it to your loyal customers to put some of these things in front of them.
Just a thought.
Gamer-X