Sales representatives sell products on behalf of manufactures or wholesalers. 
Some work directly for those companies while others work for independent sales agencies whose clients are manufacturers or wholesalers. While sales representatives don't have any formal educational requirements, many employers prefer to hire those with a bachelor's degree. Job growth in this field, in general, will be only average through 2018. Since companies will increasingly outsource this function, opportunities for employment will be better for those who want to work for independent sales agencies (Bureau of Labor Statistics, U.S. Department of Labor, Occupational Outlook Handbook, 2010-11 Edition).
If you are considering this career learn more about it by reading Sales Representative: Career Information. This article will give you basic details about this occupation, including information about earnings, educational requirements, job outlook and advancement opportunities. Since firsthand accounts can provide you with the best information, try to interview someone who works in this field. If you don't know anyone, perhaps someone in your network does. Take the Should You Become a Sales Representatives? quiz to help you decide if this career is a good fit for you.