Hi, new here and to blender, just found out about it a few weeks ago 
i am wondering how to merge 2 vertice’s, without moving 1 of them. i have already tried alt-m and merging them at the center will distort both meshes, and i am only wanting to distort one, And the merge at cursor option has the problem that you cant get the cursor in the exact perfect position you want. ill attach a picture to show what i mean. Also is it possible to make the cursor snap to the grid?
thanks for your help guys.
Use Shift-S to snap
First select the vertice that doesn’t move.
Shift-S -> Cursor to Selection
Select the vertice that needs to move
Shift-S -> Selection to Cursor
that did the trick 
thx for the quick response.