The only one I found so far is this:
http://www.language-databases.com/
At 390 euro for a language pack (e.g. English <-> Spanish), or 49 euro/month, it's a bit expensive but not out of reach. The content seems pretty good but not outstanding.
Are there any good alternatives?
Edit: to clarify, I'm looking for bilingual dictionaries (e.g. look up a Spanish word and get meanings in English)