Car swap, i mean How does this go? I see swaps options all the time on the classifieds, but don't really know if my assumption about this is right. The one with lower value car just add cash equal to the difference? Or should it be a bit more, especially if he's the one more interested in swapping? How about with same car values but different makes/models/years?

Please enlighten me on this, especially those who have swapped before.