5 Budget-Killing Expenses You'll Run Into This Weekend

After a week of cooking, many of us want to let someone else do the work on weekends, and data from the online food-ordering company GrubHub, which serves more than 700 U.S. cities, backs this up: Sunday evening is its busiest time, nationwide. Beware, though, if you're using your tablet or phone to place your order electronically. Research shows we tend to order more food when we're tapping versus talking. One San Francisco online ordering service found that because people can see the entire breadth of menu options online, they tend to throw in more appetizers, salads and other extras. Avoid over-ordering, and also consider searching for coupon codes on sites like RetailMeNot.

Outlet malls are more popular than ever, but because they're often in the middle of nowhere (thanks to cheap real estate), you may feel like you have to purchase something so the trip was "worth it." We tell ourselves that at least we got a good deal, but money-saving expert Andrea Woroch says that isn't always the case; some items aren't a deal at all. In fact, members of Congress recently asked the Federal Trade Commission to investigate the outlet industry's "potentially misleading" marketing practices, and the FTC responded by releasing a consumer guide to outlet shopping.

The average cost of taking a family of four to a Major League Baseball game last year was $210.46. Although the food in many stadiums is now a step up from hot dogs (Dungeness crab sandwiches, anyone?), you may not know that ballparks often do allow you to bring your own food and water. Check the ballpark's website before you go, since there are usually caveats (e.g., items must be in a clear plastic bag, and any food that could be easily thrown, such as apples and oranges, should be sliced or sectioned).

Those cargo carriers you can mount atop your car or SUV may allow you to bring an extra tent for the snoring camper, but they can also significantly cut your gas mileage. The Department of Energy's website for fuel-economy information recently found that hauling cargo on your roof increases wind resistance and lowers fuel economy by as much as 25 percent if you're driving 65 to 75 miles per hour. You'll get much better mileage with a rear-mount cargo box, which typically lowers fuel economy by just 1 to 5 percent.

Committing to completing a road race is a worthy fitness goal, and with the proliferation of mud runs, obstacle runs and color runs, there are an increasing number of fun options from which to choose. Just don't decide to join your friends' team at the last minute, since the registration cost can be $75 a few days before (compared to $40 ahead of time).