yeah don't expect much if anything at all for a pentium 4 computer in the year 2016...I admit, I laughed when I clicked the link and saw a pentium 4 cpu inside of an alienware pc lol.
I found a pentium 4 desktop in the dumpster here a few years ago, that's what they're worth. A 5 dollar core 2 duo decimates it...you could maybe get 40 bucks in a flea market group or garage sale...maybe. And that's only from an older non tech person that wouldn't know any better.
I'd say take it to a local pawn shop