First, to better know the value of the PC, you will want to figure out what hardware is inside since that PC can come with a number of different hardware configurations. There are multiple ways to do this.
If you have the PC up and running, install Speccy and share the results.
So, an in person sell could be $300-$350. An eBay sell $350-$400.. or more if you think it's "like new." Depends on how long you want to wait for the right buyer to come along. But I still stick to what I said at first, based on the hardware and it's performance it's about a $250 system.