I think the sale of the .se version has set a benchmark,
you really shouldn't sell for less than 15k now.
The .us version should be worth more than .se
Yes, it will take more money to set up a site and
market it, but the buyer would probably be a person
or company who is already involved in the poker world,
and would have the money to do so.
Poker seems to keep growing with no signs of letting up.
So I think the 15k would be a minimum, maybe the people
who bought .se overpaid, who knows, but I think you are looking
at at least 15k, up to 25k.
(with good promotion I don't think it would take long
to recoup 15k with poker affiliate programs, if you know
how to go about it)