I was reading a great Wikipedia article the other day. It was all about dime novels. Dime novels were cheap, paperback adventures popular from around 1860 to 1915. From what I could glean, they averaged about 30K words in length. That's about 1/3 the length of your average novel.
And that's exactly what should be priced at a buck: 30K word works. And they should be called dollar novels-not novellas-because the "dollar" in "dollar novels" sets the bar for what a reader should expect to get for a dollar: 30,000 well-crafted words. Do you see where I'm going with this?
P.S. Before someone ties me to a pike and roasts me, recall that a lot of us new-wave authors embrace the term "indie" for a reason. And I'm not suggesting this idea should be enforced in any sort of way. Only that you might want to consider the term to differentiate between your 30-40K works and 80-120K works.
Link to related blog post: http://www.bjustinshier.com/2011/05/we-should-call-them-dime-novels.html