I have a 50 Hz. Range (European) and want to operate it in North America, what would be the least expensive way of doing this. Reducing the frequency from 60 Hz to 50 Hz

Going from 60 to 50 Hz isn't generally isn't a major problem, but could be if the frequency is assumed to be 50 Hz for the controls. Check the nameplate for a 50/60 Hz designation. Call the manufacturer. You may just have to replace the controls or you may have to do nothing.