Grocery shopping on the internet is not usually frugal grocery shopping. Internet grocery shopping involves a mark up. You'll find in most cases that the advertised sales will be the same as what they offer in the store. But the UN-advertised sales, and non-sale items are usually marked up. Most often, a delivery fee is applied as well. So if you want to save money on your grocery shopping, internet grocery shopping will not be your best choice.
Grocery shopping on the internet is not usually conducive to coupons. Since grocery shopping with coupons is the best way to save, internet grocery shopping may not be the best choice for those interested in frugal grocery shopping.