Where can I purchase the necessary components?
You can purchase the components to make a reader online (see, for example, the SparkFun RFID USB Reader). Making a tag is another matter, however. Tag chips are typically sold in high volumes. If you can get chips in smaller volumes, you will need to make antennas from printing metallic inks, or by using acid to etch metal. You are better off buying tags online. They are cheap.
—Mark Roberti, Founder and Editor, RFID Journal