My memory of the 40s and even 50s is that institutional credit (banks, savings & loans) was VERY hard to come by. Credit cards hadn't been invented and many retailers provided charge accounts to regular customers whom they knew personally. If I went to the corner grocery (no massive super markets then) for my mom in 1948 or 1949, the owner and/or his clerks knew me by name and would take the note, fill the order, and carry the bag out to my little red wagon with the amount balance on mom's charge written in pencil on the bag - no cash register receipts then, either. I don't recall buying milk at the store, either. We had a milkman who delivered one or two quart bottles every day (based on the note mom left in the washed out empties on the porch.) Sometimes, if mom was cooking or baking something special, she also got a pint of cream. I remember when the milk was not homogenized and the cream would float on top of the bottle. Mom poured the milk into a pitcher and stirred it before each serving.
I remember what a big deal it was when we got a gas refrigerator (Servel brand) and no longer had ice man deliveries. Some neighbors had electric refrigerators, but it was universally acknowledged in our circle that gas was quieter and much less expensive than electric to operate. I think it helped that the gas company subsidized the cost of gas refrigerators, just as the electric company supplied free light bulbs - exchange burned out for new when paying the bill in cash at the local utility company office.