Yes, could be 'swappers' in that respect, klazo. It's not a very precise clue given the unchecked letters (even SnAPPErS can go in there - and Christmas crackers have a 'free' element too}.
I've added 'delivering' to the first part of the double def (as in delivering sexual favours) to correct the tense for the 2nd def, which helps my SLAPPERS preference a little.
Also, crossword setters seem to relish certain pejorative answers - and I don't think it's an entirely unconscious class bias!