Khan academy offers an ever-broadening list of subjects. You can learn about everything from finance to quantum physics. Not only that, but every lesson I've ever seen has been in an extremely accessible format for a broad range of users.

As a pharmacy student, I like that it has a range of material from very basic to very in depth

It is an ultimate source of learning with in-depth study material, videos, tutorials on lot of topics. It is completely free and you don't even need an account. Very good for self learning. you can search the relevant material for the topic of your interest. The assessment exams for the topic are also good and test your learning. You can ask your queries in the forum.