Get them for free mate. I rad a thread somewhere, not sure if it was this forum or another I came across.
Just call Microsoft and tell them the right trigger on your wireless pad has stopped responding. They will send you another one out free of charge. Loads of people have been doing this for the last 6 months or so.
They don't collect your old one, they just post the new one out. Also people started doing it for the hard drive, saying they took it down their mates to play some games, when they brought it back it no longer gets recognised by the Xbox.
Do the controller and hard drive in 2 seperate calls. The operator might say, wow you have just been on about a controller, as it will be on record, just say yeah, my blumming hard drive won't work now, how unlucky am I?
MS operators are not that bothered to be honest, they just give you stuff for nowt. As long as it is part of the original bundle then you are covered.
Some people got greedy and tried to get free wi-fi adapters but they were told as it was bought seperate it will be covered under warranty and this should be taken back to the retail shop for a replacement. So it only works on items that came iwth your 360 bundle.
Sorry for the longish post, but this really does work, or it was until late Sept, can't find the thread or forum to see if people are still getting away with it.