I think it depends on the customer. Probably somewhere between $50 and $300 million [1,2]. My guess is that the more successful programs will retain their current (probably defense) customers, but SpaceX will effectively serve a new generation of private companies who can take the risk. You also have to keep in mind that a lot of this is political and regulated. Depending on how a government contract swings, it might favor SpaceX or their competitors.

[1] http://www.aiaa.org/aerospace/images/articleimages/pdf/AA_Ja... [2] http://www.nationaldefensemagazine.org/archive/2010/July/Pag...