That's not a very big client list. Also having a client list doesn't mean that someone will actually come to you. Alot of people like their groomer and wouldn't appreciate their name being sold to someone else.
I wouldn't count on more than 1/4th of these clients showing up to see you. Depending on your market it may be even less than that depending on the currency of the list.
In my market I wouldn't pay more than $150 for a list like this. I probably would have better results on a blanket market spam.
In reality, unless the current owner is willing to stay on for awhile and contact clients on your behalf, it's not worth a whole lot. It's an intangible, and it's worth whatever the owner can get for it.