Read your syllabus. Each professor is different, but most want to help you succeed in their course. Those that do will give you information and links to study guides in the syllabus that can help you succeed.
Find free study guides by going to every source for free information that the university or college makes available to students. Whether it is in the form of a student success center or a writing help center, these services are usually free and very helpful.
Ask your classmates. Your peers in each of your courses are probably trying to find ways to cut down on studying time and still succeed in the class. Find free study guides by asking your fellow students what sources they are using to make studying easier. Your peers can also help by forming study groups where you can all pool your resources and broaden the free study guides you are all using.