I believe that almost any halfway decent function generator can do what Rife did, if used properly. This means wiring electrodes to hands and feet. Pulsed DC with the proper polarity (usually negative to left hand and left foot, but there Are exceptions).

For those that can't afford a ~$2,000 frequency generator designed to run Rife frequencies there are good models for as low as $250. I know of a lady that has used one of these cheapies on many people with exceptional results. I think it's more the method than the machine.