Buying in bulk is often cheaper and will save you from going to the store often. Going into the store less will keep you from impulse spending and save you time and money from transportation costs.
Use a GPS to minimize time wasted and money spent. If you use public transportation, traversing across town and switching train or bus lines is expensive and tiring.
You can also research and find a shopping strip with the most locations you need and do your shopping there. Get as much done in one spot as possible, even if it costs you more.
You can also plan your actual shopping trips. Many stores have apps that can tell you where in the store items are located. Make a list and plan the store you need to go.
If you take public transport, you can send emails, make lists, make calls, send texts, and otherwise do administrative tasks. You can even order items online and save yourself time.