We've got quite a few questions regarding desktop RFID readers for evaluation of the RFID Yubikey. Maybe we've triggered some general interest in RFID technology
There are quite a few available from various sites and the key parameters to look for is HF (13.56 MHz), ISO14443A and Mifare. Any reader meeting this criteria should work.
I find the Omnikey 5321 from HID to be a good workhorse. Best of all, it features good documentation and a broad range of drivers and code samples. The 5321 can be purchased for around $100 in single unit quantities. It is a bus-powered USB device with a built-in Smartcard reader.
HID's range of readers can be reviewed at:
http://www.hidglobal.com/technology.php ... aderType=1
A budget alternative could be to purchase a serial port OEM board without casing. Search the net for RFID MIFARE READER and you'll find several options and places to buy these readers.
With the best regards,
JakobE
Hardware- and firmware guy @ Yubico