Blade on Vauxhall Combo Keyfob need replacing?

Hi
Ive got a vauxhall combo 2003 model with the two button key fob.
like an idiot ive snapped the key by trying to open a tin of pain with it so am now surviving on the spare key with no remote.
i want to replace the blade but when i take it to timpsons or others, they stick it in some machine and say i need to go to the dealer and have it done so over £100

ive seen the blades on ebay so is it possible to by a new blade and fit it in the key and get it cut off my spare then re programme it??

any help appreciated