Originally Posted by
britenbsas
Actually, the £5 is before the 25% online discount so you can buy an advance single from Victoria to Gatwick for just £3.75 via their website
There is a catch though. The deeply discounted fares - to and from LGW - are for specific trains only, so one must commit to a train at time A on date B. Miss that train and it's buy another ticket at the walk up fare.
It may be more critical when booking a train from Gatwick to central London but it's worth bearing in mind. Still a bargain fare, innit.