There are cheap, single serving meals, such as:

• baked potato - extra lazy version is 6 min in the microwave, add toppings
• oatmeal - overnight oats, microwave (3 min, water shouldn’t quite cover oats), etc
• sandwiches - lots of options; freeze extra bread and cheese
• eggs - scrambled, fried, boiled; eggs last weeks

I got through college cooking stuff like this. It was cheap, quick to make small portions, and didn’t require many seasonings. I lived on sleek something like $45-50/month, which covered the vast majority of my meals.