Cost: Branded Viagra is available starting at $139 per ... Sildenafil is also available through Rex MD for $2 per 20-mg dose or $6 per 50- or 100-mg dose. Shipping is free on all online prescriptions.

But a generic version (and the active ingredient) of this popular medication, sildenafil, is widely available from several drug manufacturers at a fraction of the cost. Here’s more about this ...