This guy says that using Subversion and Cruisecontrol cut their costs by 92%. It would be interesting to see how he calculated this. Regardless, it is amazing how many quality tools are available for free now.
Why Subversion Rocks
In a recent study I performed on my development groups process improvement over the past 5 years, we found that we had cut the cost of managing our build and release process by approximately 92% by incorporating Subversion and related tools like CruiseControl, ViewCVS, and other custom software (and major process changes that accompany them) to integrate and automate our release management processes.