Who is the real TestKing?

I am preparing the 70-316 in the stage of practice test. I want to buy some.
h heard from this group about testking, hotcert, wsw, ...

I searched with google. can anyone tell me which one is rea?

www.testking.com, $44.99 each exam
www.testking.net, $99 for all tests
www.testking.biz, £99 for all
(they all have the same logo)
hundreds more ...

www.Hotcert.biz, $11 each exam
www.Hotcerts.com, $85 for all

I checked for 70-315, 70-316, 70-320 they all have similar number of
questions. are they same? Can you figure it out?