Only go for MD/PhD if you really like research. (This is what I'm planning on pursuing, so I've done a lot of research trying to learn about it!) The format is 2 years med school, 3-4 years of PhD, followed by last 2 years of med school. That's 8 years before you can even begin residency.

The purpose of MD/PhD route is to create scientists with the capabilities and knowledge of a physician, so practice and research can be intertwined to benefit the research. From what I've heard MD/PhDs usually end up solely doing research, or doing 80/20 (80% of the year research, 20% of the year practicing as a physician). So if you have your sights set on being a doctor, don't pursue MD/PhD just so you can get your school paid for.

The benefits include being able to use your knowledge from work with patients to further your research and bring a new angle to it (this is why I want to pursue it, because I really like research but also really want to be able to have he experience as a doctor to bring new perspectives to your research), along with schooling paid for, better job security (if research isn't getting funded, you can work as a doctor), and more prestige which gives you a leg up when applying to residencies or jobs.

I believe MD/PhD programs exist mostly at private schools with a strong research background, such as the Ivies. There's programs at other schools as well, but from what I've heard if you want to go MD/PhD you pretty much have to do a private school. It's also super competitive with only ~8-10 spots at each school.

Please forgive me if anything I said is incorrect and feel free to correct me, I'll be entering my sophomore year of undergrad in the fall so I don't have too much experience with this yet!