I agree w/Mickey on all points. I would suspect that the sellers would take it if you said no. BUT, if you said yes, I wouldn't offer them any $$$ for it. Tell them you'll take it but you want it as an INCLUSION with the house deal. (Get it listed on the Real Estate Txn form regarding Inclusions/Exclusions if they'll leave it. Otherwise, they can say one thing and end up taking it if it's NOT on that list!) If they baulk, then it's up to you. You did say it's a fridge and not a freezer-fridge. If it's the latter, if it's a frost-free freezer, it costs more to run. If it's not, it costs less to run but it needs to be defrosted periodically if your home is a humid one. BTW, have you looked at the utility bills for the last 12 months? If not, ask for them, and see that you get at least the last 6 months. Gas bill, electric bill, oil bill, water bill, sewer bill, etc., etc..
(Back on your original subject ...) Have you asked why the seller wants to sell the fridge?! My best to ya and hope this $.02 helps.