When I published my print books with Createspace, they had to be at least $10 on Amazon, so I priced them at $12.99. I've left them at that price, because I'm really not focusing on print anymore, and they don't sell anyway.
I've played a lot with ebook pricing. At first, every ebook I put out was $5.00. Then all the other indies started publishing at $2.99, and I began to wonder if $5 was too much for an indie ebook. So I'm in the middle of a pricing experiment, with my books between $.99 and $3.99. Thus far, pricing is making a negligible difference in my sales, but if you head over to Konrath's blog, I'm clearly an anomaly, so...
For me, it doesn't make a difference what length the book is, it's all about how much money I can make from it at whatever price I set it at. So my two longest titles (both around 90K) are at $.99 right now, in the hopes of increasing sales. The sales, thus far, are not increasing, however, so they'll probably go back up to $4.99 in April. If I'm only going to sell 2-3 copies of each a month, I'd rather make $3 on them than $0.35.
My best selling ebook (which is steady at about 30-ish copies a month) is $2.99. My $.99 ebooks are not selling like hotcakes. (Though my vampire novella did sell about 14 copies last month. I released it midmonth, so that was about one sale a day. I thought the $.99 thing was working, but...this month, it's only sold 3 copies.)
Overall, my sales are in a holding pattern, which is about 100 or so copies total (of all my books) a month since December. This has not increased (much) by adding more titles, or by screwing with price. In other words, I have no freaking clue what to tell you.
It's really a guessing game. What price will make you the most profit in the long run? Will a low price attract a large number of sales? Will those people be willing to buy your other books at a higher price? One title at $.99 cents makes you peanuts. I think the $.99 strategy is better used if you've got other books, especially in a series, which are priced $2.99 or higher.