For one thing, you may want to consider shopping for staple items like rice, flour, or even canned foods. While it may take some additional time to prepare items like these, they are usually relatively inexpensive when compared with other items. Also, items like these are either non-perishable or have a long shelf life, increasing their value since there is less chance of wasting them.
Also, consider buying generic brand items. What your grandmother says is true – they’re just as good as the store brand! And they’re often considerably less expensive. Besides that, due to this pandemic, store brand products have been selling out even faster than generic brands.