is there a maximum dollar amount that scribd adheres to with respect to including titles in there $8.99 per month subscription for their customers?
Unfortunately I don't know the answer but I wonder if there can be a limit as they claim you can read anything, in any format, on any device. This does make me wonder about their business model though. I guess they count on most people signing up and then never actually bothering to read anything.
I know on Kindle your books have to be priced between $ 2.99 and $9.99 to be in the Kindle Select programme which lets people borrow your books. Kindle used to pay out an amount (determined by the size of the fund and the number of borrows) if someone read 10 % of your book. They now pay out roughly half a cent for each page read when your book is borrowed.
On Scribd you make a sale when someone reads 30 % of your book. This would seem to suggest that short books (and by extension, cheap books) stand the best chance of generating a sale.