Medical billing and coding is a very popular work at home job. Since all of the files and such can be taken home and doctors can avoid having another person clogging up the office, it's easy to make the transition from an office job to work at home medical billing jobs.
WARNING: Ignore those e-mails that you get telling you that you can make thousands a month just for typing, doing transcription, medical billing, or whatever... those sites just want you to sign up for their "guaranteed system" and "secret list of companies"... it's all a load of garbage, really.
If a company has a job opening, it's not a secret. There are many online classifieds similar to your local newspaper, and most work at home medical billing jobs can be found here. Companies don't have the time to keep their information "top secret" or to make people pay for application information.
Now if you find a career blog or website that has a membership fee to belong, that's a different story. It might be worth your ten or twenty dollars each month to have them find the work at home medical billing jobs for you. If you don't want to pay, you can find the job listings on your own using sites like Craig's List and Career Builder, as well as others. There are plenty of online job boards that you can research on your own to find work at home medical billing positions, completely free of charge.
Working from home is becoming an increasingly popular trend, for obvious reasons. Not just anyone can work at home though. You need to be disciplined, dedicated, and committed to getting the job done. With a home based job, you're on your own. If you can't handle that kind of responsibility, stick with the office job.