TENS offers great relief to _some_ patients. Not everyone finds it effective. For those that it works for it is very highly regarded. This modality of treatment is very low risk and very low cost. Please consult a physician before starting any therapy. I personally find it very effective for Morton's neuroma.
Please pay attention to the contraindications.. patients with implanted pacemakers or defibrillators should NOT use a TENS unit without close consultation with their cardiologist.