Is $699 a good deal for a used jcm 800 head?

I was at guitar center today and they have a used jcm 800 head for $699. Is this a good price? If I get it I dont know how much tubes cost or which ones to buy to replace the old ones. Two more things, what cab should I get to go with it and what overdrive pedal can I put in front of this amp to make it scream?

well it comes down to the fact if you have the money and if thats what you want. Brand new this amp will come out 1700 as a half stack. The JCM 800 is one of the best amps out there. I'm sure you can check out ebay for the head and ive seen tons go for 500 or even less. As for the cab i love celestions so maybe some greenbacks or vintage 30's would be nice to go with the head.