Leanpub and Gumroad are two services that follow this strategy. I don't know if they are successful ventures, but I notice they have maintained this pricing strategy since their inception and never changed or stopped it.
Leanpub says "...the pattern we have seen with multiple books, about a third of people will pay the suggested price, a third will pay the minimum price and a third will pay somewhere in between. Finally, the odd person will pay more than the suggested price" [1]. Some anecdotal experiences of individual authors [2],[3],[4] support it.
[1]: https://leanpub.com/help/author_faq [2]: http://blather.michaelwlucas.com/archives/1626 [3]: http://blog.ppenev.com/2013/07/16/what-i-have-learned-from-l... [4]: http://blog.gumroad.com/post/75707736685/is-pay-what-you-wan...