Poetic injustice: First the airlines started charging for checked luggage, prompting more flyers to carry their bags instead. Then they tried to slap on a charge for carry-on bags too. When "low-cost" carrier Spirit Airlines proposed a $45 fee for carry-on items in April 2010, even U.S. Senators got angry, introducing a bill to tame Spirit and warn other carriers. But the legislation has made no headway, so, effective in August, be prepared to shell out if you want to place a bag in an overhead bin on Spirit. Thankfully, none of the big airlines have matched the fee — at least not yet.