SpaceX isn’t the only launch company boasting about cheap launch prices. According to this GigaOm post, Firefly is a company that will be trying to compete with SpaceX. The rocket they’ll be using is a different design, not using traditional bell nozzles to guide the rocket’s power, but a system called an aerospike. And, just guessing here from information given on FireFly’s site, the aerospike is a “flat plug” cluster style configuration (see image below). You can go to this page and this page for more information about the aerospike and it’s different configurations.
The aerospike will be a part of their FireFly Alpha rocket. FireFly is using the aerospike to help reduce rocket weight (getting rid of the bell nozzle) and gain efficiency throughout the FireFly Alpha’s flight, which will probably help to increase the rocket’s payload capacity. The payload capacity is quite small–400 kg (882 lbs).
However, FireFly is not intending to accomplish heavy-lifting with the FireFly Alpha. They are instead going for the swift-growing and expanding small satellite/cubesat market. Companies like Planet Labs are working with constellations of small satellites, and FireFly is extremely interested in being the company small satellite builders think of when launch requirements need to be hammered out.
GigaOm also noted that FireFly will be selling entire FireFly Alpha at a cost $8 0r $9 million dollars, which is significantly cheaper than the base $50-90 million dollars for a SpaceX Falcon 9 rocket. But since the FireFly Alpha’s payload carrying weight is smaller than the Falcon 9’s 29,000 lbs, the price per pound is still a little more than SpaceX’s. Also, note: GigaOm inaccurately is using the name Falcon Heavy for the Falcon 9 in their post. While the Falcon Heavy can technically carry payloads over 14,000 lbs (it’s projected to lift 117,000 lbs), I think the writer meant the Falcon 9 in the post’s payload weight comparison.