College is the new high school and having just one bachelor's degree does not set you apart from other job seekers. Many people consider getting two bachelor's degrees to give them an academic edge in the job market. However, getting a second degree can add time and cost to your education so it should not be done without some thought.
Getting a double major can take additional time depending upon what majors you choose. If you get two majors that are closely related, like anthropology and psychology, you may only add a few summer semesters. If you work toward drastically different degrees like fine arts and electronic engineering, you could add years.
The cost depends on the majors you choose. If the majors are closely related, you can get a lot of cross credit and save on tuition. Some schools offer discounts on classes if you have already earned one degree from them. However, the cost can easily double if the majors are opposed, again like dance and electronics engineering -- you would need different dedicated electronics tools like a multimeter for electronics and dance shoes for dance.
A benefit of working toward two degrees is that you may be able to obtain cross credit for your classes, especially if you are getting your degrees at the same institution. For example, your upper-level psychology class could count for your basic humanities requirement in electrical engineering. What classes qualify for cross credit depends on your institution, though there is significant wiggle room if you present a compelling argument to the dean in charge of those majors.
A big benefit from having two degrees is that it makes you stand out from other job seekers. For example, having a degree in accounting and business makes you more appealing for a corporate accounting position than someone with just an accounting degree -- especially if you are willing to work for the same pay. Dual degrees also gives you more options, someone with electrical engineering and mechanical engineering degree could work for a large corporation and probably get a signing bonus because of your greater versatility.