Car Key recoding

I recently lost my car key for a volvo which is attached to the alarm remote control etc which I believe is coded to the car and without it the car won't start.

Now I have one key left but am now extremely concerned of the consequences of losing that one.

I've checked with the dealer and a new key/control is over €400.

I've looked on ebay and can get the exact same key fob for €10.

Obviously I will have to get the key recut and attached to this fob but can anyone with some experience tell me if it is possible to recode this fob or the car so that it will work in my car.

I've done some searches on this but found an endless about of confusing contradicting statements.

You would probably have to take this to the dealer to be recoded and they would only do this if they were happy that the fob was a genuine part.

On a Volvo it is dealer only.Volvo dealer will not touch second hand remote.

I'd love to know why certain car keys are so expensive.

Found the same for Alfa Romeo, having bought the genuine part from the garage was charged another €75 for them to encode it.

The guy who encoded it just brought out my original key, key card and new key to my car.

Would be interested to know the method he used, seems a lot of money for 5 minutes work.