Someone or another at the pub last week was joking that they'd rather have RFID tags on stuff than barcoding things. Well, turns out you can get tags and readers quite cheaply - http://www.zygo.btinternet.co.uk/offer011.html They're 30 quid for a basic rs232-based reader, and a couple of quid for extra tags. If there's lots of interest, I might be persuaded to coordinate a bulk buy - drop me a mail, and I'll mail anyone back next week, either with prices, or to let you know to just buy them individually.
the hatter