I tried two kinds, sorry, I've forgotten their names, for 3 months each. Neither did much to speed up enlargement, all they do is give you harder erections.
Not worth wasting your money!
You might have seen my thread about Tongkat ali, it is similarly priced but has a much more noticable effect on libido and penis hardness than penis pills. I only took it for 2.5 months but when I can afford it I will start taking it again - potent stuff! With high doses over a long period, some people have noticed enlargement just from taking it alone, I didn't notice any accelerated growth however.