what do you carry your baby in?

When I go shopping I either have my two month old in a shopping cart (in his carrier) or I bring his stroller. I'm going to this place that doesn't have shopping carts and I feel weird bringing my baby in his stroller. Also I think he's too heavy to be carrying around his carrier. I have a carrier where i strap him to me but I've never used it and don't feel as comfortable using it anyway. What do you all do?