You can get a flight itinerary to show immigration officials for a visa without having to pay for the flight by using a flight itinerary company or booking a dummy flight.

A flight itinerary is useful for your visa application process. A flight itinerary looks like a confirmed flight booking, but it is not an actual ticket. https://schengenflightreservationvisa.com/

You can also try booking a dummy flight. This means you book a flight that you have no intention of taking. The purpose is to have a flight itinerary to show immigration officials. You can easily cancel the flight later or change the dates if needed. Just make sure to check the airline's cancellation policy before booking a dummy flight.

Please note that the information you provide to immigration officials should be accurate and up-to-date. Suppose the information provided in your flight itinerary is found to be false. In that case, it could have serious consequences, so you must be careful and honest in your dealings with immigration officials.