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

Comparisons of some VCS tools

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)