Scalping is the shortest time frame in trading and it exploits small changes in currency prices. Scalpers attempt to act like traditional market makers or specialists. To make the spread means to buy at the Bid price and sell at the Ask price, in order to gain the bid/ask difference. This procedure allows for profit even when the bid and ask don't move at all, as long as there are traders who are willing to take market prices. It normally involves establishing and liquidating a position quickly, usually within minutes or even seconds.
Market data is necessary for day traders to be competitive. A real-time data feed requires paying fees to the respective stock exchanges, usually combined with the broker's charges; these fees are usually very low compared to the other costs of trading. The fees may be waived for promotional purposes or for customers meeting a minimum monthly volume of trades. Even a moderately active day trader can expect to meet these requirements, making the basic data feed essentially "free". In addition to the raw market data, some traders purchase more advanced data feeds that include historical data and features such as scanning large numbers of stocks in the live market for unusual activity. Complicated analysis and charting software are other popular additions. These types of systems can cost from tens to hundreds of dollars per month to access.
The bid–ask spread is two sides of the same coin. The spread can be viewed as trading bonuses or costs according to different parties and different strategies. On one hand, traders who do NOT wish to queue their order, instead paying the market price, pay the spreads (costs). On the other hand, traders who wish to queue and wait for execution receive the spreads (bonuses). Some day trading strategies attempt to capture the spread as additional, or even the only, profits for successful trades.