How much should I pay for this?

Hello to all, new to Comanches, not new to jeep, but I was looking to buy this Comanche I found right up the road from where I'm working, anyways it's an 86 long bed not really that much rust on the cab, but it has the ring and pinion out of the rear, and has an oil leak in the 2.5l, 4 speed and he said that the 4wd worked fully. It needs the normal wear and tear stuff fixed just wondering what I should offer the guy,needs painted as its not the original color, has 150k miles and the gas gauge does not work. Also it says it's a remanufacture on the title. I was thinking 600 bucks??