Sounds like a good deal to me, as long as it is not stolen.
eBay prices ( top dollar )
1) tx ( controller under $100 )
2) extender ( $80-$100 )
3) charger ( $40 )
4) battery ( $90-140 )
Your looking around $700-$750 that is paying top dollar for parts.
I'm sure you can find them cheaper if you look.
New still $975. Your saving a few HONDO!
I have an extra Tx with extender and mounts ( from a crashed phantom 2 vision )
I might even have a charger? No batteries though , sorry.
Hit me up if you buy it. We will work something out ( my extender is modded with external antenna )
The biggest problem you'll have is getting QR CODE for your camera, I think you can contact DJI to get it
You need it to bind your extender to your camera on phantom.
Take care, Good luck!
J Dot