Try not to spend a lot of money on food on the way to a vacation; it can get really pricey
. Never buy food at the airport. It is crazy expensive and can cost you a lot of money and a lot of pounds, because it is normally not very healthy. Try not to eat on the plane either. The food is expensive and often tasteless there, too. Do carry small snacks however; these are not confiscated by airport security. Also you can save yourself a few bucks by bringing an empty water bottle and filling it with the airplanes tap water.