Tell you a cheaper way mate.
Stick an electrode with a wire attached, up your
and connect the wire to a good earth.
I really must bone up on things again as I have been in aviation for 4 decades and never heard anything about non sparking shoes. I lot of those years was with aircraft, with engines that run on avgas! Never heard of and aircraft going up through static from sparky shoes. Guess there is a first time for anything and everything.