Others are working on it: Boeing's CST-100, Blue Origin's orbital spacecraft, Sierra Nevada's Dream Chaser.
Cost per seat on the Soyuz to LEO range from $20m to $68m with this 2010 article saying $51m.
SpaceX has said they will charge $20m per seat. With an F9 launch price of
The Dragon has been over designed from the start to be a universal lander (Red Dragon.) A Falcon Heavy (FH) will be able to put a fully fueled Red Dragon in mars orbit in preparation for crew transfer and landing for $150m. The FH will have it's first flight later this year and can lift 53mt for a cost ranging from $80m to $125m.
The FH has the potential of launching a Dragon derived shuttle with much more than seven passengers (say 50) to achieve a much lower cost per passenger. This could potentially bring the cost to LEO per passenger down to around $2m per.
Update: It Begins.