Are you mad?
What happens when down the line, it breaks, you lose it, it gets stolen, you drop it, etc...
Keep it, cos you may get $700 for it now, but when your only unit breaks down and you have to find someone willing to sell you one to replace it, its gonna cost a lot more than $700.
I just wish at the time I'd had enough money to buy four of them. Bought a couple of car sleds for additional cars in the future, or if my car is stolen and never reovered. You can always buy a new car, but in 2 years time where are you going to get a sled from?