can i use a second hand keyfob for my central locking on a chrysler grand v?

I have just brought a 1998 chrysler grand voyager that has no central locking keyfobs due to previous owner loosing it but was told I could use a second hand one from another crysler voyager but would need to have it re-programmed. Is this true? or would the whole system have to be replaced? If its possible would it have to be one from a grand voyager or would any crysler do? I have seen many people selling S/H keyfobs but is this just a scam?