I don't know of any online CVS/Subversion services that are free (assuming that's what you mean by "service"?), except for those that offer "personal" or "basic" plans with a limited amount of data and number of users. Depending on how small your "small team" is and the expected project size, maybe one of those would work.
Search for things like "cvs server", "subversion hosting", etc. and you should find a number of things to compare.