Spot foreign exchange (exchanges of foreign currencies) brokers - They do not charge any commissions because they make profits from the bid/ask spread quotes. On July 10, 2006, the exchange rate between Euro and United States dollar is 1.2733 at 15:45. The internal (inter-bank dealers) bid/ask price is 1.2732-5/1.2733-5. However the foreign exchange brokers or middlemen will not offer the same competitive prices to their clients. Instead they provide their own version of bid and ask quotes, say 1.2731/1.2734, of which their commissions are already "hidden" in it. More competitive brokers do not charge more than 2 pips spread on a currency where the interbank market has a 1 pip spread, and some offer better than this by quoting prices in fractional pips.
Scalping can appear easy because a scalper might make an entire day's profit within a few minutes. However, in reality, scalping can be quite challenging because there is very little room for error. If you do decide to try scalping, make sure that you do so by using a trading simulator, until you are consistently profitable and no longer make any beginning mistakes, such as not exiting your trades when they move against you.
You're probably looking for deals and low prices, but stay away from penny stocks. These stocks are often illiquid, and chances of hitting a jackpot are often bleak. Many stocks trading under $5 a share become de-listed from major stock exchanges and are only tradable over-the-counter (OTC). Unless you see a real opportunity and have done your research, stay clear of these.