I've taken 5-HTP, and noticed a definite difference in the way I felt, and how well I could sleep. I stopped using it, when I started having a vision anomoly, that neither the optomestrist, nor the opthamologist could diagnose. I later found that my vision problem was due to the need for a prism in my glasses.
I have recently started taking 5-HTP again, about an hour before bed. I seems to make a difference in how quickly I fall asleep, and how well I stay asleep. My problem is remembering to take it. As far as price is concerned, I found good prices and reasonable shipping costs, at iherb.com.