How much to fix my SIM card reader because it keeps saying I have no service or it will say searching

You have to call the Apple store.

I don't think this is an Apple service center's official help forum. Please contact the Apple care helpline ot visit the store personally. One suggestion, make sure your phone and the sim belongs to the same network provider. Besides that,there might be a chance that the phone's antenna is broken, rather the sim reader.