Sorry if this is a faq, I am italian.
The question is: which is the cheapest way to go from Gatwick airport
to
Heatrow airport (and viceversa)?
Outbound is on 19th may, inbound is 23rd may.

Here's my suggestion for the cheapest way to get between the 2 airports.

1) Buy a "Network Away break" train ticket between Gatwick Airport and West
Brompton, this is a return ticket and there are direct trains on weekdays
every hour. Cost £16.40
2) At west brompton get off the train and go to the ticket office in the
station. Here ask for an oyster card with £5 pre pay credit on it. (You'll
need to pay a £3 deposit to get the card).
3) Use the oyster card to take the tube from West Brompton to Earls Court
(District Line). Here change to take the Picadilly Line direct to Heathrow
Airport. This part journey will use £2.30 pre-pay credit up on your oyster
card.
4) On your return, again take the picaddily line to Earls Court then to West
Brompton. As this is a weekend, the journey will only cost £1. At West
brompton, take your oyster card back to the ticket office and get your £3
deposit back and the remaining £1.70 credit on the card.
5) Use the return part of the Network Away break to get the train from West
Brompton to Gatwick Airport.

Total cost = £16.20 + £2.30 + £1 = £19.50
It might be complex, but it is cheap!!! Depending on the time of day, the
journey may take up to 3 hours.

The only problems you *may have*
- You may need to change trains at clapham junction, as on the sunday there
may not be a direct train.
- The ticket office at west brompton may be closed. That means you'll have
to use the ticket machine, which will charge higher prices.

Ian