Keyfob battery dead

[big dub]

I have a 2002 Passat and the battery in the keyfob died last night.

Do I have to take it back to VW to get changed (how much?) or is there another cheaper way?

Cheers

[Who me ?]

Possibly your handbook should tell you how to open the fob .In the likely event that it is a button cell ( such as 2032 -roughly sizeof 10p, ) Asda do them (2032) at a reasonable price .If it's a different no -
try this site
http://www.battery-house.co.uk/batteries.html

for an equivalent .
Then perhaps Maplin

[Dr G]

You should be alright, I'm almost certain it's CR2032 for those. Pop it in the key, put key in the ignition and press lock/unlock a few times. Unlesss it's been completely flat for a while you shouldn't need to recode it.