Sorry to be the bearer of bad news but its actually going to cost you in excess of £200 once you take into account that you need to have the key programmed to the car. You could actually get a non remote key (ie no buttons) which would be ok as a spare, that would cost approx £80 inc the programming. Drop me a PM if you are interested or would like any more info.
I bought a key of ebay the same as my car key £20 inc postage
Then I got a new blade which is attached to the black cover Got the blade cut to my key so it worked in the ignition while they did that they took the insides out of the key from ebay in put them in the new cut key £15
I then took both keys to The local Honda Dealer in Southport who then reprogrammed them both with the car £28