NEW YORK (CNN) -- CNN Money's Maribel Aber has your top business and financial news on this Tuesday, September 24.
How a shutdown could affect the economy
It would be inconvenient and frustrating. But how much would a federal government shutdown affect the economy? It depends on how long it lasts. "The effects build over time: Two weeks is worse than one week, and three works is still worse than two weeks, and four is still worse than that," Congressional Budget Office Director Douglas Elmendorf said last week.
Best credit cards
It's more expensive to carry a balance, with annual percentage rates on new cards averaging 15.31%, up from 14.30% in 2010, according to Bankrate. On the plus side, 0% intro periods have gotten longer, going from eight to 11 months on average over the same time, NerdWallet reports. You can save hundreds -- even thousands -- by transferring a debt and paying it off within the interest-free window. Or you can take advantage of the 0% trend to pay for a big-ticket purchase over time, at no cost.
Wal-Mart Stores to expand jobs for 70K workers
Wal-Mart Stores is hiring 55,000 seasonal workers and is elevating 70,000 more to part- or full-time positions as the holiday season ramps up. The world's largest retailer said Monday that 35,000 temporary workers will become part-time and 35,000 part-time workers will gain full-time jobs. The shift means that Wal-Mart will be offering more of its workers benefits. That's significant because Wal-Mart has been a target of attacks by labor groups for what they say are skimpy wages and benefits.
Apple sells record 9 million iPhones in opening weekend
Apple announced it sold 9 million of the new iPhone 5S and iPhone 5C models since they went on sale Friday -- a record opening weekend for the iPhone. That's nearly double the 5 million iPhones that Apple sold during the first three days that the iPhone 5 was on sale last year, and sales were well above Wall Street analysts' expectations. Shares of Apple (AAPL, Fortune 500) rose 6% Monday morning.