Why do I need a Version Control System?
Refer to these articles:
Visual Guide to Version Control
Visual Guide to Distributed Version Control
Good excuses NOT to use version control
Example Costs
These costs are indicative only. Contact the supplier for exact costs and for purchasing the licenses.
Perforce - Free for up to 20 users and 20 workspaces, or unlimited users with up to 1,000 files, or for OSS or educational use; else $900 per seat in perpetuity, with volume discounts, or $360 per seat on a subscription model
Team Foundation Server - Free for up to 5 users in the TFS 11 express edition or for open source projects through codeplex.com; else non-free, licensed through MSDN subscription or direct buy
Vault - $300 per user
Subversion – Free
Git – Free
Mercurial – Free
Kiln built on Mercurial (Maximum $25 per user per month hosted. Including bug management - $30)