The ShengShou Master Pyraminx is the cheapest Master Pyraminx on the market but does perform quite well. The master pyraminx is a pyraminx with one more layer than normal, this completely alters the solving technique, the first step is to solve the corners and middle edges as if it was a normal pyraminx, you then have to fix the centres, once you have done that you can begin pairing up all of the other edge pieces, the final 3 or 4 of these edge pieces may be a bit tricky to figure out sometimes. Buy it here