I've been a website designer for over a dozen years and programming with Joomla! for less than six months, and I can't agree more with mwerthjoomla regarding changing information on the fly (CAUTION: watch ampersands while doing this!) without accessing the plug-in preferences (I have 10 items on one of my first EasyPaypal client websites that were very easy to program). mwerthjoomla and squatterjoe are also right on target regarding the support. Bing is wonderful - excellent and incredibly quick customer service!
And Molly is right: the $10 it costs is money well spent.
My advice to all is read all of the reviews with a keen eye toward the details (whys and whats) of the reviews and keep them in mind when "shopping," but I think you'll find this extension is just what you want.
Thanks again Bing!