How do I classify reimbursements I’ve received for mystery shopping?

I’ve been doing mystery shopping as a side job. They have you go to a variety of places, check out the business, purchase something (which they reimburse up to a certain amount), and write up a report about the service provided. For example, if I get an assignment to go to a restaurant, get paid $5, and get reimbursed up to $10 for the meal I’m required to purchase to review, how is that supposed to be reported on my taxes? I didn’t make enough for them to send me a 1099, so I’m not sure how it breaks down. Is it reported as $15 income with a $10 deduction? Or is all $15 income and none of it is deductible? If the $10 reimbursement for the required meal purchase is deductible, what do I put it down as? I know there are categories for meal expenses that are 50% and 100% deductible, would it be one of those (if so which one?) or neither? If I also made required purchases that were reimbursed at a different type of store that’s not food, do I need put those down in a different category? I just want to put it down the way I’m supposed to, I’ve tried checking different places and have no idea what to do, thank you for your help.