Aldis Super Market Chain uses that system here. They are the only one I know of, and I've never heard anyone complain. The store doesn't have to pay workers to go collect carts from the parking lot. But whatever Aldis is doing allows them to undercut other grocers prices, including Walmart. Possibly Costco as well, although I haven't done a price comparison with Costco yet. They don't bag your groceries either, so I have to cart my stuff to the car, and return the cart after I place their groceries in a trunk caddy that I bought specifically for Aldis groceries. But I don't mind the inconvenience when a business returns the favor with lower prices, on some items less than half the price. However, Aldis stock is more limited, and sometimes I have to get things from Walmart.