A question regarding doing simple business while studying at university?

I've never been an entrepreneur. And i'm heading off to university this year. As most of you know university tuition and costs are outrageously high these days so I'm looking for a business idea to do while studying at university. Business that doesn't require much time. Plus university is only 8 months of study per year so i get to take 4 months off a year while in it. Can you help me with this please?