Just remember, the only reason prices go up is because some punters agree to pay them.
It is also called charging “What the market will bear”

If you want to get technical, look up Price Discrimination:
"If a seller can, they charge different customers different prices based on their willingness to pay (e.g., airline tickets, hotel rooms, petrol prices, software tiers). In the extreme case (called “first-degree price discrimination”), a firm would charge each person exactly their maximum willingness to pay.