There are two new Viagra alternatives on the market. One is Levitra, which works similarly to Viagra but supposedly works a little faster. The second one is called Cialis. It just became available in the U.S., but Europe has had it for awhile. They say this one absorbs faster and stays in the body up to 36 hours (versus 4 hours on average with Viagra). I bought some from an online pharmacy; got it in about 3 days. I haven't tried it yet but I will soon. Check the Internet and judge for yourself.

Herbal products are not as consistent or potent as viagra. You can try Yohimbe which has worked for some people, but I have tried both and viagra is superior by a wide margin. Be careful with  yohimbe as it will get your heart racing.

I am not sure about your reasons for wanting non-prescription, but if you want something that works well and has very few and slight side effects use levitra. It is almost as strong as viagra, works faster and longer and at least for me has little if any effect other that the one desired. Cialis in my opinion is a waste of money as it produced almost no effect at all.

You may find it at Health Food stores.  I am not sure if you have the grocery chains Whole Foods or Wild Oats.  They sell it.
The stuff is very good.