I had eighteen seam ripper holders made by a friend who does woodworking. He cut 3"x3" cubes of wood, then drilled a hole that fit the COVER of the seam ripper, then gave each cube a light sanding to remove the cut marks. When I want to use it, I inserted the handle in the cover. When I'm finished with it, I turn the seam ripper over and insert it back in the cover. By inserting the cover in the hole, I will not lose it or the seam ripper and I will never stab myself accidentally.
I gave each person in my bee one of these for Christmas, and still have some left to give as a gift.
And the cost? $2 each for the holder plus the cost of the seam ripper.