Single Personal use:
My suggestion will to use any local server installation on your PC / Laptop, and then have regular backup to any external drive or drive cloud service. My recommendation will be the free edition of Visual SVN Server.
If you don't have an issue that your source code will be shared worldwide, pick from below listing:
If you want to have closed source between your group members check below case for start-ups.
Start-ups / entrepreneurs:
With limited budget, unlimited number of users, project management features, collaboration, issue tracking, redundant backups, pick from below listing:
If you have reasonable budget, looking for complete SDLC (Software Development Life Cycle Management) / ADLM (Application Development Life Cycle Management), complete collaboration between distributed teams, trusted company by major customer references with lots of plugins / marketplace you may expand at anytime based on your needs. Atlassian will be the best for you; this can range from small to large enterprise.You will need the following products as start:
You can find Gartner report shared here. Customer references shared here (List includes: Nasa, Twitter, Facebook, BMW, Audi, Cisco, Adobe, ...).
Hope this helps someone there.