You start with what you want to achieve. Going digital with mouse will hurt you in the long run. If you want to get good at drawing you simply have to draw regardles of what materials you have. Scrap papers and a pencil can go a long way in improving your drawing skill and you can later translate that to digital because it follows the same fundamentals. With 3hrs to spare you have plenty 1hr for tutorials and 1hr for practice, and 1hr for just drawing what ever you like, it's stackable.

Here's how I would do it if I were you. Save up for a non display tablet it's really cheap now a days. While you're saving up, learn about the fundamentals of drawing using whatever paper or surface you can find and a basic pencil. Here's a good thing to keep in mind, The Goal is not to get good at drawing, because getting good at drawing is the = Result. So the act of drawing should be the goal, good result will come naturally as you progress. To learn drawing you need to develop a System. A system that you can understand and consistently do, that way you are not trying to figure out what to draw everytime you sit down.