If you can spare the time, look into git! Source Control is a free GUI for it.
A lot of people in this forum will tell you to pick SVN because they don't understand git, but the truth is that git is much more powerful and flexible.

The thing with git is that it has to make click before you truly see how fucking crazy powerful it is, although it is already useful before that. I can't recommend you a Tutorial, I heard good things about this ebook: http://www.git-tower.com/learn/, but take it with a grain of salt and if it's not to your liking, google one.

Like... Git may seem hard and you do have to put in at least a bit of upfront learning, but it will absolutely pay off in the long run.