A throwaway ticket and a temporary onward reservation can look like solutions to the same problem: you need to show how you plan to leave a country, but you are not ready to commit to the final journey. The better choice depends on whether you intend to fly the booked segment. Buying a cheap airline ticket just to abandon it may seem clever, but it can create unnecessary cost and complications. A temporary reservation is worth considering when the document you need is a reservation rather than an issued ticket.
What is a throwaway ticket?
In this context, a throwaway ticket is a real airline ticket purchased with no intention of taking the flight. It is issued and paid for, but the buyer expects to let it go unused. People sometimes choose this route because the fare looks inexpensive or because they believe only a fully issued ticket will satisfy the person checking their documents.