SparkFun Simultaneous RFID Reader - M6E Nano Long Distance UHF Sensor Shield Write Tags at 80msec Standard Read up to 150 Tags/sec to 96-bit EPC

Good product

These are great little RFID readers. I use this on a Linux system with python using the Mercury API python wrapper. This thing can read a huge pile of tags and fast. I've watched the real time results and it's very impressive. I wish the reader was a little bit cheaper, but it is one of the cheapest options on the market and very capable. The main reader chip itself is about $120 alone, so the rest of the cost is the board it sits on with the internal trace antenna and a couple other connections i don't use. Either way, it's a excellent rfid reader!