They are obviously an awesome speaker if you have ever heard them. Yes, they do like a lot of juice--I wouldn't even attempt less than 200 wpc if you really want to hear what they can do.
From what I have seen, current market value is in the $600-900 range depending on condition and area of the country.
They can be bi-amped, so if you need more juice, you might be able to use what you have and add a second amp.