I spoke to someone at Wolfram about using the API about 6 months ago and they said they would try and get me access to their "Pioneer Grant" which is the free version of the API. No word since then. The pricing for the regular API is prohibitively expensive. How did you intend to use it?
I didn't want to use it for anything terribly sophisticated; I wanted to make a lightweight web application for people to track their dietary history. WolframAlpha would make it pretty simple: http://www.wolframalpha.com/input/?i=1+slice+pizza,+2+cups+g...