A basket of 35 popular items cost £84.90 in September, 3p less than the previous month but £1.81 more than a year ago, according to mySupermarket's monthly groceries tracker.
Many fresh food essentials increased in price throughout September, with onions costing 16% more, mushrooms climbing 11%, carrots up 6.5 % and grapes 4% more expensive.
However, a number of student food staples dropped in price - such as pasta, down 4%, red pasta sauce and baked beans, both down 3%.
Overall, the cost of 20 items rose and 15 fell.
MySupermarket chief executive Gilad Simhony said: "We're always happy to report a fall in basket cost and the price reduction on store cupboard staples is good news for families on a budget as well as students returning to university.
"Unfortunately, it is once again fresh produce creeping up in price which is not good news for both shoppers' health and wealth.
"The news that the same basket of goods costs £1.81 more on average in September 2017 compared to 2016 shows that it is more important than ever for shoppers to do their research to get the best value for money."