Poor buying when things expensive they are expert buying top in everything and FOMO in also the middle class are expert on buying highest prices and not just buying they buy it with credit.
Rich buys when something is with good price low price poor buys just to spend money.
Middle class behave like poor too they buying expensive.
Actually, many middle class folks follow trends or leap in when prices are high due to FOMO. Though typically motivated by emotion they believe they are investing or acting smart. Usually waiting for sales or discounts the rich make ahead plans. Sometimes it's more about attitude than about money.