I used to be able to find the One Touch units at some of my local drug stores.
Using too much salt water solution is a real problem because once it gets inside the probe holder it shorts it out.
I have tried using other parts of my body as an alternate path for the current without success so I continue to use the probe holder. I have found that if I cut a small piece of kleenex to 3 times the width of the band, fold it 3 times so it ends up the width of the band and wrap it around the band (2 to 3 turns) that this provides a constant
(but not overly wet) salt solution.
Depending on how much hair you want to remove, be prepared to purchase a couple of units. I have however, learned to straighten the probes with tweezers so they last me quite a while but the probe will eventually wear out. Fortunately, the One Touch is not that expensive and overall the cost of hair hemoval is still a fraction of having it done commercially.
The one modification that has proven to be extremely effective was to add a foot switch between one of the wires from the battery to prevent current from flowing until I feel I have the probe positioned correctly. This has increased my success rate dramatically.