Spread trading This high-speed technique tries to profit on temporary changes in sentiment, exploiting the difference in the bid-ask price for a stock, also called a spread. For example, if a buyer’s bid price drops suddenly, the day trader might step in to buy and then try to quickly resell at the stock’s ask price or higher, earning a small “spread” on the transaction.
Scalping can be very profitable for traders who decide to use it as a primary strategy, or even those who use it to supplement other types of trading. Adhering to the strict exit strategy is the key to making small profits compound into large gains. The brief amount of market exposure and the frequency of small moves are key attributes that are the reasons why this strategy is popular among many types of traders.
Scalpers need to be disciplined and need to stick to their trading regimen very closely. Any decision that needs to be made should be done so with certainty. But scalpers should also be very flexible, because market conditions are very fluid and if a trade isn't going as expected, they'll need to fix the situation as quickly as possible without incurring too much of a loss. 
There are a variety of methodologies to capitalize on market swings. Some traders prefer to trade after the market has confirmed a change of direction and trade with the developing momentum. Others may choose to enter the market on the long side after the market has dropped to the lower band of its price channel—in other words, buying short-term weakness and selling short-term strength. Both approaches can be profitable if implemented with skill and discipline over time.
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.