Specifically referring to the cost of the orbiter vehicle itself (or the cost you'd incur building a replacement if you lost one), roughly $2 billion is a decently accurate figure. The shuttle program as a whole, yes, is drastically more expensive.

"The Space Shuttle Endeavour, the orbiter built to replace the Space Shuttle Challenger, cost approximately $1.7 billion." http://www.nasa.gov/centers/kennedy/about/information/shuttl...