[Kirtai]

I'm more likely to read free books by unknown authors because I'm more likely to get them. It's a matter of convenience; if I see a free book that looks vaguely interesting I'll grab it, if I have to pay then that requires more thought and possibly more work (registering with sites, digging out credit card info, etc) which I might just not bother with.

Of course, if it's an author I already know I like then that's different.