@Chris Coyier - I hadn't thought about the price control angle but, I wonder, might that actually give a "free market" boost to sales, with some sites cutting into their own margin in order to move more volume?

Or, would the variance in pricing blow the lid of the whole affiliate game, making regular people realize that all those "recommendations" have a dollar motive behind them?

We had legally enforced pricing on books here in the UK, supposedly to protect small bookshops, but all it really did was keep books ridiculously expensive, forcing poorer families to rely upon libraries and second-hand bookshops.

Minimum pricing was finally dropped in the early Nineties, allowing the Supermarkets to enter the business and massively reducing the price of books overall. If we hadn't dropped enforced minimum pricing, Amazon.co.uk, with its heavy discounting, would never have been able to operate effectively in the UK.

The immediate problem for you, however, is that affiliate sales of digital products seem to be unworkable in it's current form. The reselling approach I'm suggesting could be a fix and, I suppose, there is no reason why minimum pricing couldn't also be enforced as part of the terms.