It is fair to say that stock trading at a few cents a share is the most risky investment anyone could make - many experts would say foolhardy in the extreme. The temptation to buy thousands of shares for a few cents is one that often results in many people getting their fingers burned. What you have to remember is that there is a reason the stock is so cheap - it really isn't worth much and the likelihood of making a killing on such shares is far from the foregone conclusion that some people will try to convince you it is. Establishing the likely performance of these stocks is usually virtually impossible as often there is very little information available on the companies to do any kind of meaningful analysis.
Don't be lured into buying stocks just because a newsletter or email tells you it is a sure thing. There are plenty of sharks out there who will engange in the practice known as "pump and dump", whereby they will attempt to generate unsubstatiated hype about a particular stock in the hope that there will be a rush to buy, enabling them to sell on their worthless holdings to unsuspecting hopefuls. You really must excercise caution and do your own "due diligence" - if you don't, you will soon end up regretting impulsive penny stock purchases.
Trading stock online is not difficult, and once you have a basic understanding of how it works and decide to give it a try, you will need an account with an online stockbroker.