The cost varies from place to place, depending on their cost to use the facilities. Here in Tampa the total cost was $450, including the $100. deposit. Again, after the deposit, it is whatever you choose to pay. At double the price it would still be such a bargain for the way it can change a marriage.
Retrouvaille is not a cure-all. They teach you the skills to repair your own marriage. I agree with HB, you never learn that in MC. The work is yours to do without a third party commenting on your ideas. And when you are better, you know that you did it yourselves too. It really makes you feel more powerful, because you know that you can help yourselves when you need to.
The website is http://www.helpourmarriage.com. Asking him to do it for you, or as an ultimatum often works. He will have to tell them that he is going willingly with an open mind.