I have Peugeot 306 '97. I had to take the battery out and after replacing the battery my stereo is asking for a code which I don' know. I have tried phoning few audio shops but they are quoting �25-�30 for decoding. I have tried pressing Band button and then pressing poer on utton and the stereo switches On for about 5 minutes and then it asks for code again.
I know that for certain manufacturers, if you visit their Service Department with the registration and/or VIN, some proof of ownership, they will give you the code. Some for free, some for a small charge - �10 ish.
This obviously only applies if the radio is the original equipment fitted at time of manufacture.
I had the same problem with my 306, go to the main dealer, if it's the original radio, all the codes are on a database that they can access, but they charge you a fee (�10) for the privilige!