vanity toll free phone numbers

[reliable1]

I have a client that owes me a very substantial amount of money but they have been hit very hard by the economy and are nearing bankruptcy. They are offering me some domains and toll free phone numbers - most of them are 800 numbers which are fairly impossible to get any more and some of them are quite valuable in that they spell a word without numbers. 800 numbers are like the dotcom of vanity phone numbers.

That said, I don't know how to sell or monetize the 800 numbers. Does anyone have experience with selling vanity phone numbers and could offer suggestions?

TIA
Paul