RFID readers and tags required

I work at a gaming centre, and we plan to install RFID card readers that can be connected to a central server through ethernet. Customers would be issued RFID cards, and the credit in their account would be stored in the server. When a customer wishes to play, he/she simply uses his card, the reader identifies it, verifies from the server that the card holder has enough credits, and then begins the game, sending a message to the server about the same, whereby the server deducts the requisite credits from the particular account.The reader should also be able to send a pulse to the game CPU after it has verified the account details and balance of the card from the server, so that the game can begin. For this, an in-built relay with both NO(normally open) and NC(normally closed) connections would be preferable. If that seems difficult to do, though I don't think it will, we will at least require output terminals where such a relay can be connected externally. However, an in-built relay would be ideal. I am looking for cheap , but reliable RFID readers for this purpose.