How much are replacement reomote control keys for BMW 318se?

I think I need to replace my key for my car as it is intermittent in when it wants to work,so please any ideas on how much this is going to set me back.Thanks in advanceHow much are replacement reomote control keys for BMW 318se?Approximately $140 to $200 in the US (depends on where you are and how greedy the dealer is).