Best popup/mouseover translator that's free?

Hi,

I use mandarin popup in firefox, and it’s great except that it does not recognize compound words.

Is there any similar tool that recognizes compound words? Free would be my preference. I have found a pretty nice one called mdbg but it’s $50. Is this the only game in town at the moment?

Thanks

The Popup Chinese Firefox plugin handles words, not just individual Chinese characters.