I've always worked Friday and Saturday nights, it is when most buisnesses need high school kids to work. The thing you need to look for is a place that closes around 9 or so. I used to bag groceries in high school and would be out on the weekends by 9:30. Plenty early enough to do as I chose the rest of the night. But I would suggest looking for a place where they close early enough to where it doesn't runin your weekend. Unless you have a curfew and than 9:30 may be limiting your time severly.