Even with five  billion dollars spent already on the the Orion capsule, it will still need a billion dollars a year for many more years :

• NASA Audit Warns More Delays, Cost Growth are Possible for Orion – SpaceNews.com
• NASA IG Worries About Programmatic Risk to Orion Due To Funding Constraints
• NASA’s Orion Multi-Purpose Crew Vehicle (IG-13-022) – NASA OIG  (pdf)
• Video: Audit of NASA’s Orion Multi-Purpose Crew Vehicle – NASA Office of Inspector General

Five billion is far more than will be spent on the Commercial Crew Program, which by 2015-16 will have two and perhaps three crew vehicles ready for flight. Orion’s deep space capability in no way justifies that huge difference in cost. The SpaceX Dragon and the Boeing CST-100 as well are plenty capable of deep space missions.

A combo of a Dragon with an inflatable habitat module such as that from Bigelow Aerospace is the transportation architecture of the Inspiration Mars mission.