You know how they say, 'a purse so large it could fit a kitchen sink,'? Well my purse is really that large and contains pretty much everything a mom could want including my kid's vaccination records, recent pay and bill stubs, snack containers/packets, handi-wipes, hand sanitizer, clean undies (packed in ziplock) for the rare occasion one of the younger ones has a whoops moment as well as some assorted travel entertainment such as kids books. My bag is a little heavier than I'd like, but I don't really spend that much time holding it. At this point, maybe I'd be better off lugging around an overnight bag.
I have a purse somewhere around here but never really use it. I have a small cloth clutch that I use (it was a camera case at one time) that has a keyfob on it for the car and house keys. That's where I keep my credit cards and car info. That goes to the store with me when I leave the house.