But you also deserve to do that safely. The information provided is for educational purposes only and is not intended to replace discussions with a healthcare provider. Viagra will last at least four hours and as long as 12 hours in some individuals. It will not spontaneously cause an erection. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.25– mg: branded Viagra, sildenafil, branded Cialis, generic Cialis: Lemonaid: $2 per dose: 20 mg: sildenafil, tadalafil: Optum Store: $1–$6 per dose: 20– mg: branded . · Walmart: $ Sildenafil: CVS: $ Sildenafil: Costco: $ How to get sildenafil without insurance? Ask About Generic Options. Sildenafil: 20 mg / 30 tablets *Lowest online price at national pharmacy chains Costco, CVS, RiteAid, Walgreens and Walmart as of 1/19/ Prices vary by location and pharmacy, see . Quoted prices are for cash-paying customers and are not valid with insurance plans. This price guide is based on using the discount card which is accepted at most U.S. pharmacies. A generic version of Revatio is available. See sildenafil prices (from $ for milliliters).