One thing that is too common in these aerospace related budget estimates is that they go up. I am trying not to be pessimistic, but I have a feeling that their launch costs might go up a little bit. Even if it does it, their prices would still be groundbreaking nonetheless. I bought Dr. Zubrin's book on mars direct (its great!) and lets say that somehow the cost to send three spacecraft with the capability to come back (including development costs) is $10 billion (which I am pretty sure is a super under estimate but the spacex way might say otherwise). To put that into perspective google could have funded a full fledged manned mars mission and still save $2 billion to spare by not buying motorola...

But this is definitely possible even with nasa's reduced budget now that the shuttle is retired.