If you are taking a course, then I would expect the course tutor to advise you which tools you will need.
If you're new to web design, I'd advise you to spend as little as possible at first, until you know whether this really is something you want to pursue. All you need to get started is a basic text editor, and some kind of image editing software. A code editor, which highlights different aspects of your page, is probably easier to work with than a plain text editor, and some of these are available free, or have a free trial version. Just try a few and see which one suits your way of working.
We have a couple of sticky threads which will give you some ideas: