THE only furniture in the ''checks cashed'' outlet is a waste-high table jutting out from the wall. There are no eye-catching advertisements for patrons to look at. The walls are formica, the floor is linoleum, and the teller is barricaded behind a bullet-proof window. Despite their bare-bones decor, check-cashing establishments are steadily becoming the financial centers for many consumers in America's lower-income neighborhoods. With bank fees increasing overall, and fewer bank branches available in poorer communities, check cashers offer what banks cannot: longer hours and a wider range of services. As a result, their business is booming. Today there are more than 5,000 check-cashing outlets in the United States - more than three times as many as 10 years ago, says Henry Shyne, executive director of the National Check Cashers Association in Paramus, N.J. Approximately 15 percent of Americans cash $50 billion worth of checks every year at these establishments. ''In today's economy, middle-income people are living from paycheck to paycheck, and they can't wait for their check to clear,'' Shyne says. ''Check cashers provide immediate cash and that is what people obviously want.'' Check-cashing establishments do not offer checking and savings accounts. Their primary business is cashing checks. But consumers also can buy money orders, pay monthly bills, and purchase lottery tickets and public transportation tokens. ''As far as we are concerned, we are the neighborhood bank,'' says Edward Toledano, president of Uneeda Check Cashing, who runs 24 stores in Manhattan and the Bronx. ''Banks are just not equipped to handle our type of customer.'' One of the main reasons for the increase in check cashers, says Glenn von Nostitz, director of research for the New York Office of the Public Advocate, is that the consolidation of the banking industry has significantly reduced the number of branches banks operate, particularly in poorer communities. Consumers may also be reacting to a steady increase in banking fees. ''Banks are getting more and more difficult to deal with,'' says Harry O'Neil, vice chairman of Roper Starch Worldwide, a polling group. ''They are putting fees on everything now and that allows the banks to avoid dealing with lower-income customers,'' he says. In New York state alone, the check-cashing industry has grown from a $4.1 billion business in 1981 into what is currently a $10 billion industry, a 1994 survey by New York's Office of the Public Advocate found. A single check-cashing customer with an annual income of $17,000 will pay almost $250 a year at a check-cashing store compared with $60 for the same services at an inexpensive bank, the survey showed. Mr. Shyne says these figures do not take into account the extra charges banks have for overdrafts and not maintaining a minimum balance. The survey also found that in locations where check-cashing outlets do not have any competition from banks, fees on cashing personal checks can climb as high as 10 percent. Shyne admits that because 38 states in the country do not have any licensing regulations, some businesses charge too much for cashing checks. ''Like any industry, we have our share of bad apples,'' says Shyne, who notes that the average charge for cashing a check in the US is 2 percent of its face value. Fritz Elmendorf, a spokesman with the Arlington, Va.-based Consumer Bankers Association, argues that banks still offer services in poorer neighborhoods. ''We find that check cashers can co-exist with banks because they offer different types of financial services than banks.'' Carlos Medina, who fills out a check for his electric bill at EGI Check Cashing, says ''check cashers are ideal for making payments that I have forgotten to make. This place is just so convenient for me.''