$5 dollars for 100mg Viagra! That sounds too good to be true? I think if your paying anywhere around $10 dollars that's very good. I usually use to pay about $13 dollars for Viagra when I use to buy it, as I usually get Levitra now, but I usually go late at night where my choices are limited. But I guess anything is possible?
I also used the generic 50 mg Viarga they sell from about $7 to $9 dollars, and it works pretty good, and for some reason TJ pharmacies like to push it? But I rather buy the real thing when possible.
I never brought fake Viagra that I know of in a fake Viagra box.
Don't forget to bargain if you feel a pharmacy is charging you too much. If they want $18 dollars for a Viagra just tell them you can buy the same thing for $13 or $14 somewhere else, and they will probably match it without tax, but I doubt they will go down to $10 dollars like the large super stores charge.