I use a jar opener, round rubber w/holes, purchased at the dollar store & it works fine. I carpet.

At home I have my foot pedal on top of a 2x12 board to get it a little higher (my cheap way of not getting a table to set my machine down in to and still be able to sew comfortably in the highest position my chair will let me.. I have a piece of vinyl of some sort on top of that and it doesn't slip..
When I sew at my guild's sewing days, it's a smooth vinyl floor. I cut a piece of that rubbery bumpy shelf liner paper - you know the cheap stuff that you can buy at the Dollar Tree? That keeps my pedal from moving anywhere at all. It's sweet :)

i now have a non traveling foot pedal. thanks to the foyer rug, it is missing a little extra padding that was doubled over. what a difference it makes. doesn't sit 100% still, but soo much better than it was.