Read the terms and conditions carefully before signing up for a Viagra free trial or sample pack of Viagra because there can be other costs or requirements attached to the offer. People can increase their chances of receiving a free sample of Viagra by mail by being proactive and remaining informed. Its effects often last for 4 to 5 hours. The inability to obtain or sustain an erection strong enough for sexual engagement is the hallmark of ED. Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil.Optum Store Sildenafil If you are experiencing the symptoms of erectile dysfunction (ED), you may have considered using Viagra or a similar ED medication as a possible . Pfizer, the manufacturer of Viagra, offers a program that can help lower the cost of Viagra. For more information and to find out if you’re eligible for support, call or visit. Most popular Low price Walmart $ retail Save 99% $ One-time offer Get free savings Walgreens $1, retail Save 99%.