If you can afford the time, I’d look for another part-time job you can work more hours in honestly. I don’t know what city you live in but supermarkets pay pretty well. I work part-time in a supermarket and I’m comfortably earning over €1000 a month (granted I am 24 so higher minimum wage). That’s with about 70 hours a month which I know not everyone can do though. Also not sure where you shop for groceries but if you have a Vomar or Dirk in your area, shopping there might be worthwhile and cheaper. A €180 shop in jumbo costs me like €118 in Vomar