seconding Land's End - I bought their mid-thigh length puffer coat in 2017 and it's still going strong. Super warm, hood is detachable, pockets are lined with sweater material AND zippable, and internal cuffs at the wrists to trap heat. I'm 5' 4" and the normal XS fits me well, but it also comes in petite if that's your preference.

source on quality of coat: I lived in Chicago and wore it in 0 F weather.

Best of all, Land's End is probably the only place you'll be able to find a good long puffy coat (which is the coat you will need below 30 F) for around 100 dollars. Otherwise the price for a good coat is usually 200-300. Just wait for one of their 50% sales and you should be under the 100 dollar mark.