Well, I just plugged in a random genre fiction book (A Sea of Swords by Salvatore) and looked at the kindle price: $5.59. Since that had a professional editor go through it, I figure I gotta at least chop a dollar off. That was a slightly older book.
Checking a slightly newer fantasy genre book, I see $5.99 for A Wise Man's Fear by Rothfuss. Quite a bit thicker there too. Also has a professional editor.
So yeah. I don't feel to bad figuring $3.99 should suffice for what I"ll end up doing. But maybe I shouldn't go that low. I'm still waiting on a few more rejection letters before I fully consider this route anyways.
$2.99 is the standard price for indies with nothing to their name, at least in the standard 70-80k+ range. $3.99 is fine for 100k and up it seems, but I've seen it recommended not to go higher than that until you've established yourself. Hell, there's people putting up 160k epics for .99.
The exception is of course erotica, which you can price at $2.99 with 5k words because people will buy it if you know what you're doing.
I do worry that this race to the bottom will be damaging for the publishing industry in the same way that mobile game pricing has dramatically changed the video game industry.