The ticket price will let you differentiate between the two of them instantly. While budget airlines sell incredibly cheap tickets, full-service airlines generally set higher prices, even if they have a sale. However, travelers must remember that the cheapest airfare offered by low-cost carriers usually includes a seat only and every single service, such as food, in-flight entertainment, changing your booking, etc. is paid extra. In the end, the ticket price may be quite costly without keeping this in mind.