I'm a relatively poor startup founder and I can't say the $5 different is yet to sway me on ebooks, quiet happy to pay $10, although I'm not the fastest reader

I'm a relatively poor startup founder and I can't say the $5 different is yet to sway me on ebooks, quiet happy to pay $10, although I'm not the fastest reader around. Above $10 though pushes it and $20 feels over the mark to me unless it's something directed at a niche audience.