Well, from my personal experience, it all depends on exactly what you're looking for. No, there is no such thing as a male enhancement to grow your penis by 2-4" inches. It is impossible for a single pill which I actually used several types of "get-bigger-pills" for more than 3 years jumping from one, to another and nothing meaning no size gain of not even an inch.
However, there are many pills online that are a scam and completely fake which all they want is your money. Especially those free trials samples. Yet, there are actually a few male enhancement such as the VigRx Plus which have cured thousands of men worldwide in sexual impotence for over a decade. Basically, all it does is make you hornier and if conjuction with an extender, pump or penile exercises, it "may or can" help increase penis size since it boosts up blood flow to the male organ. But not just the pills alone won't work to add size if that's your looking for.
Btw for your sexual needs and safety, I'll handle you the link where it tells you exactly what it can do and not. This is the most one that I personally trust for sexual function, health and impotence.