Well there's no real "correct" price, it all depends on what the current demand is like. Still you need to provide more information, such as what the physical condition is like, if you've got AppleCare on it and what (if any) accessories are included.
The 2015 model is available from Apple refurbished for $929, with a full warranty and new battery, so thats a good starting point for comparison.
On eBay one like yours just sold for $631, with about the same battery cycles. So I'd try to get $625-650 for it on eBay, perhaps a bit less on CL, etc.