In the next few years there’s going to be an influx of a not-so-new technology called Near Field Communication (NFC), which is very similar to RFID, and enables small devices to read passive tags and communicate with each other in close proximity. Card readers use it, as do phones that do payment processing.
Adafruit’s PN532 NFC/RFID controller breakout board v1.3 can do it all with NFC and RFID, reading types 1 to 4 of both standards. The board provides read and write communication though 3.3V TTL UART at any baud rate, I2C, or SPI, and is supported by the open source general NFC library libnfc. The device-specific Arduino library provided by Adafruit currently only supports a read function, but there are plans to expand it.