My brother recently did a DNA test with a member of GenesReunited to see if we were related. Our surname is Coppin but the other was spelt with an 'e' instead of the 'i'. It cost £75 each, which was paid by the 'possible newcomer into the family'. Much to our delight the test proved that we did indeed have a common ancestor, born 1717, which made us 5th cousins. We arranged to meet in Addington, where the family had lived for 300 years or so, for lunch. Trouble was, that as soon as I saw him I knew that 'he be one of ours'!!! He looked so much like my aunt's boys that had we exchanged photos before the DNA test we could have saved him the money!
All I can add ( this being my first foray into this site!!!!) is to try swapping photos before you pay out for a test!