Upload & Sell: Off
I'm so confused. The price wasn't unreasonably low, it was good but not like "oh wow it must be stolen" by any means. Especially with the d800 refurb deals going around and such.
People do stuff like this all the time, some reasons might be:
1. Buy something and decide it isn't what you want but don't want to return it (ethical reasons perhaps, or store charges large restocking fee, etc).
2. Buy something that you want to use for a month or two then sell it at a little loss, essentially getting a cheap rental.
Or, how about this (very very likely) one:
3. You get some rewards points with your credit card that you can only spend at a limited number of places OR you get a big gift card for one store, etc. You want cash instead and you want it now! So, what do you do? Buy something then sell it and price it so it sells fast. (this is quite common)