Sweet! Walmart has the Nerf Rival Prometheus Blaster with 200 Nerf Rival Rounds for only $74.99 Shipped! (Reg. $200) This is one of their HOT Black Friday Deals. Experience the intensity of this Nerf Rival toy blaster that bombards opponents with up to 8 rounds per second! The fully motorized Prometheus MXVIII-20K blaster holds a whopping 200 rounds in its easy-loading hopper and fires rounds at a velocity of 100 feet per second.