Propane has a wide variety of uses, including food additive E944 (a propellant gas for packaged foods such as whipped cream), a popular refrigerant R290, but most commonly a household/motor fuel and a primary component for gas flame applications. It is important to note that in everyday life there is usually confusion: when "propane in bottles" is mentioned, it typically means a special propane-butane mixture used as fuel (it has a higher calorific value than pure propane). It should be clearly distinguished in which cases pure propane is used instead of a propane-butane mixture, and in case of doubt, refer to the accompanying instructions for the device.
Technically, refueling of propane cylinders (combustible propane-butane mixture) is carried out at special filling stations (gas points), and in the case of vehicles - at the so-called gas filling stations (they should not be confused with CNG filling stations, where refueling is carried out with compressed natural gas - methane). If there is an equipped gas point, filling with propane of a household cylinder can also be carried out at a gas filling station, although this is not recommended. To easily detect leaks, it is customary to add a so-called odorizer to propane fuel or its mixture - a substance whose smell is easily detected even with minimal leakage. Usually, ethyl mercaptan (EtSH) acts as an odorant - and it is its smell in everyday life that is called the "smell of gas."
Thus, before asking the question “where to buy propane”, you should clearly define what kind of gas and for what needs you need: very pure propane (for example, for an imported refrigerator) should be sought at a service center, and the fuel mixture at a gas point or gas filling station.