This one is a well-known tip for a reason; it just works! If you need to buy non-perishable goods that you use often or a lot of then provided you have the cash flow it makes sense to buy it in bulk.
I love my fruit and vegetables, but one thing that I will never do is buy them out of season. If you are buying fruit or vegetables out of season then you have to expect they will be more expensive.
I was amazed at how much cheaper my weekly grocery shop was without meat. Meat-free Monday could be a good way to dip your toe in and save money on groceries.