Produce
Deli
Seafood
Meat
Condiments, oils and extras
Dairy
I always read the backs of everything, if it has sugars I don't buy it, if its 5g carbs or less I buy it. All these things you will see on a recipe for Keto. Read my recipes, try your own, or search the internet.
This is my list of groceries for Keto. I buy a few extra things for my family that I will not eat, but this should get you through the first 1-2 weeks. Always plan a menu before shopping. Fresh food goes bad a lot faster than boxed food. Your carriage will look like you have less in it, but it's just because you will not have bulky boxes taking up space.