You don't have to be a Prime member, just Subscribe & Save and all grocery orders ship free.
http://www.amazon.com/b/ref=amb_link...rd_i=cereal%20
Some stuff is no better than sale prices at my local store, but when I know I'm going to need it, it's easier for me to have it brought to my door. Toilet paper, seasonings, cold cereal, laundry soap, etc. that's bulky and hard for me to handle/carry. Sometimes they have good coffee deals and that's a time to let them carry a case of it to the door for me.
I'm pretty gimped up and winter in MI is extremely difficult for me with the scooter, parking lots, etc. so that's how I got involved in it.
If you know your prices at home, you might want to run your shopping list through an online store and compare cost per item to your latest bill. You'll know.