My cheap gaming rig

I’ve been to several LAN parties recently, and have been getting a very accurate understanding of how much a pain it is to lug around a 30lb case, 30 inch monitor, and all the accessories. I’ve looked at gaming laptops; they all seem too expensive, too expensive, and too slow compared to something I could build myself, for cheap. The total cost for the project needed to be under $80. I already have a good gaming rig, and the convenience of such a thing is only good if the cost is low.