Apple has an their usual list of Mac apps for college students on their web site (not to be confused with similar lists for iPad/iPhone).

The apps selection is very good. I use most of their suggested apps very often, many daily.

There are, however, many other inexpensive apps that are especially useful for college students and professionals. Here is a supplemental list in the form of a mind map. Click on the map to expand it. My selections serve to significantly broaden the overall range of useful tools and I personally find all 11 apps to be indispensable.