I'm visiting London for one day next month. I'm flying into Gatwick and getting the train into London. Is it worth buying the train ticket in advance? I've been looking online and prices vary widely between different websites. And I can't actually find out it would cost to buy on the day.
I normally fly into Stansted and buy my (very expensive) train ticket on the day as I've never managed to find a cheap ticket online.
So I'm just wondering since there seems to be more choice of train lines and companies at Gatwick should I buy in advance.