I agree with what JFK is doing using a freezer and temp controller rather than a fridge, a freezer is the way to go.
A fridge will struggle to get close to 32*F if it can even make it and once the door is opened it will struggle to get back to whatever temp you are trying to maintain. You might be thinking I don't need 32*F but I you ever decide to do a lager, you will.
A chest freezer will keep the cold air inside with the door opened so that it won't have to work hard to get back to temp once the door is opened.
New units will cost more to buy, used units will cost more to operate, as a general rule.
And last but not least is this advise: Buy cheap and buy twice.