Someone explain to me the difference between Hard Ops, Box Cutter, Mesh Machine and Machine tools?

Do you mean MACHIN3tools?
And yes it is actually a free toolset but BM has a minimum price of 1$ for anything sold…

The DeusEx version I believe is 10$± , and worth it in my book, as It includes the Edge Constrained Transform tool, as well as Group Gizmos and the Punch It tool.