Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. It is also used to treat pulmonary arterial hypertension, a serious heart and lung condition. This drug is more popular than comparable drugs. It is available in generic and brand versions. Generic sildenafil is covered by most Medicare and insurance plans, but some pharmacy coupons or cash prices may be lower. The lowest GoodRx price for the most common version of sildenafil is around $23.00, 55% off the average retail price of $51.33. Compare PDE5 inhibitors.