We also looked at additional services, such as access to digital pharmacies and home delivery options. That’s not to say there aren’t just as many illegitimate sites. All PDE5 inhibitors, including Viagra and Cialis, require a valid prescription regardless of the pharmacy or provider. Cialis tadalafil : This ED medication works with the same principle as Viagra, but lasts up to 36 hours. Finding an online ED provider can feel overwhelming. Other warning signs of an unsafe online pharmacy include outdated medication, no customer service, or suspiciously low prices. Finally, we checked customer reviews to better understand user experiences with each platform.What Medications Are Available? All of these work by relaxing your muscles and boosting blood flow to your penis, making erections easier to get and maintain. They are: avanafil . Get sildenafil for as low as $, which is 99% off the average retail price of $ for the most common version, by using a GoodRx coupon. Prices Medicare Drug Info Side Effects Images Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. GoodRx can help you save over 80% off the average retail price of the generic versions. Generic sildenafil at certain pharmacies is as low as $ with a free GoodRx discount. You can also find generic tadalafil and vardenafil for as low as $ and $ , respectively. What’s more, you can find brand-name Stendra for as low as $ .