Don't know the program, don't know what past pricing was but saw this on a UK site. If it's now free I ama ssuming the pro version anyway at soem time wasn't.

"Mobipocket Reader 5.1 Pro Now Free

With Mobipocket Reader 5.1 Pro (Freeware), you can read all the ebooks in the Mobipocket ebookstore - including dictionaries, synchronize enews channels, view your personal documents.

Version 5.1 adds support for MS Office import, Adobe PDF, text and HTML documents, as well as support to synchronize bookmarks, annotations, reading lists, and book metadata between devices. "

http://www.mobipocket.com/en/DownloadSoft/default.asp