According to the iTunesConnect_DeveloperGuide [https://itunesconnect.apple.com/WebObjects/iTunesConnect.woa/wo/5.0.0.0.0.5.1. 1.5.1.7.1.11.3] there is a link in iTunesConnect called "See Pricing Matrix".
I didn't find the Pricing Matrix until after I selected a pricing tier. A specific tier number seems to match pretty closely to the desired dollar amount you want. So tier 6 will be $5.99.
It's in the contract for Paid Applications that you had to 'sign' when you did the iTunes Connect set up. However, I don't know of a way to get back to it.