If you've ever thought about changing careers you've likely hesitated because of the financial risk. Switching careers might require more education or even a second (or first) college degree. There's never been a better time to go back to school than now thanks to apps and websites like Coursera.

Coursera is an online learning platform used by around 24 million people. It allows anyone to take classes, earn certificates and, in some cases, degrees.

Classes are taught by professors from some of the leading universities from around the world: Stanford, Michigan, Johns Hopkins, Princeton, Yale to name a few.

When you first log on to the app, you're asked if you want to advance your career, start a new one or if you just like to learn new things.

West Virginia University has a class on Forensic Accounting and Fraud Examination.

The class starts July 9th. I can enroll in the course and earn a certificate of completion for $49, or go through the class for free without receiving a certificate. You get all the course material, online lessons and lectures, and you'll take quizzes graded by the professors.

There's a huge catalog of courses in just about every field of study; business, arts and humanities, math, science, and language as well as self-help and meditation.

I found a free online course called "Philosophy, Science and Religion", taught by professors from the University of Edinburgh. This course can be taken for free and after I enrolled I had access to course material for the class and could watch weeks of lectures from the school's professors. Some courses are free, others cost around $40.

You can also earn full degrees online through Coursera; a Masters in computer science from Arizona State is $15,000 which is a bargain when compared to the actual cost of tuition to attend the school on campus. Scholarships, grants and loans are available.

You can use Coursera through the free apps as well as through the website.

If you're serious about changing careers, going back to school or just learning something new, Coursera is a good place to start.