Ain't nobody buying a third-hand gaspipe fixie conversion with frame clearances you could fly a plane though. Not for $200 and certainly never $300.

It'd be the sort of thing you'd build for your own personal use, because you're stoney broke and you need something that works as quickly as possible. Been there, done that.

Clean it up, ride it a while. As is it's a practical bike, and it'll be better than riding a mountain bike onroad. Not worth tarting up.