By JOYCE M. ROSENBERGNEW YORK (AP) â¿¿ If you're one of the nearly 60 million people in the U.S. who work at small businesses, the nation's new health care law likely will affect you in some way. Starting this week, public exchanges, or marketplaces, are opening up in each state to sell health insurance. Bryan Shaw has coverage from his employer 3dcart, a software company in Tamarac, Fla., but plans to shop on an exchange. Shaw says he's excited about the fact that insurance companies large and small will be competing for customers on the exchanges. He expects that competition will lead to a better price for the insurance he needs. Here's what you need to know about the law: Q. How do I find out what coverage my company is offering? A. Companies with fewer than 50 workers aren't required to provide insurance. Those with more than 50 must provide affordable coverage. Ask your company about its plans to provide insurance, including details about premiums, deductibles and other costs, says Zoe Barry, CEO of ZappRx, a Boston-based company that manages patients' prescription information. Q. My company isn't required to offer coverage and isn't going to do it. What are my options? A. Public exchanges set up in each state under the new law are designed to sell affordable coverage. Each exchange offers insurance plans from several companies. Coverage is divided into four levels: bronze, silver, gold and platinum, with premiums at the bronze level being the cheapest and platinum the most expensive. Deductibles and out-of-pocket costs are larger with bronze plans, and shrink as you go up the scale and pay higher monthly premiums. The government will subsidize coverage on the exchanges if an individual's income is no more than $45,960 and up to $94,200 for a family of four. You can also buy insurance through a broker, on a private exchange or directly from an insurer, but it's likely to be more expensive and it won't be subsidized.