After rent, food can be one of the biggest expenditures when you're at uni, but there are ways you can try to cut costs. For example, towards the end of the day, often supermarkets cut the cost of some items dramatically. This could be because the food has a short best-before or use-by date, but you could always just shove it in the freezer and get it out at a later date.
Aldi and Lidl are the no frills (value), often no brands supermarket but they make a big difference to how much your shopping can cost. According to the Student Money Survey food is the second biggest expenditure for students, coming in at £92 a month. This might seem like a substantial amount. but it breaks down to just £21 a week, which is a reasonable amount for a weekly food shop and any meals out and takeaways.
Plymouth Supermarket Search