Here in Australia these shops are called Op shops. A lot of people I know shop at them and not only if you don't have much money, but to recycle, reuse, re-purpose.
One girl I know buys jewellery at Op shops and makes them into other jewellery.
I recently spent $6 on six items from the $1 rack, which is a rarity, and I have a book addiction and so I buy a lot of books there too. One of our local shops has the majority of their clothes for $2, it is the only one in our area to do so.
Our son is now 19 and volunteered in an Op shop for a couple of years when he was at school and after for a bit too and knows he gets more bang for his buck there when he needs something. He doesn't have a lot of money and is careful what he spends it on, he is happy to spend more money on things he really wants and is important to him but he always researches his prices and often buys second hand.
I do know some people who despite not having a lot of money, will not shop in Op shops and laugh at those of us who do. However, they have said "oh but you are rich", NOT, they don't understand that we don't spend on always going to the movies, eating out, buying clothes new, buying expensive groceries.
We don't do those things so we can have the money to do things that are important to us, like travel and live out of town on our little acreage, and enrol in courses for further education.