My main price-point for eBooks is, well... $6 (quantity 1), with substantial discounts for buying in bundles. Whether the book is in $26 hardcover or $7.99 paperback. (Guess which publisher has captured the majority of my eBook $
In the far-less-common circumstance where the eBook didn't come from Baen, I'll pay up to 75% of the commonly-available price for the recent paper edition for a non-DRM eBook. Or 50% of the commonly-available price for the recent paper edition for a DRM-polluted eBook. But for DRM=polluted books, I think very hard about whether or not I want to buy at all
... and usually wind up passing on the book entirely.