There are a lot more issues for supply chain companies that are looking at implementing RFID into their process than just the cost of the tag.
They need to consider investment in technology, current system integration, and the bandwidth to handle huge volumes of tags in one spot (like a truck driving through a entrance, and a reader capturing all tags)
Back in 2003 the Auto ID Centre in the US did some predictions on the price of RFID tags into the market place.
It is interesting to look at the chart produced by the Centre almost 5 years ago. They envisaged two scenarios: (1) By 2008, EPC tags have come close to reaching the mythical "5-cent" tag, and there would be "fast adoption"; (2) tag prices stay higher, and there is "moderate adoption.”
Clearly the adoption of RFID has been slower than expected and at best is their second prediction. We are a while away before we really see RFID become a significant force in the tracking of products.
NB: RFID means Radio-frequency identification (see wiki) and are small tags that generate a genreally unique radiowave, which can be read by devices without having to scan bar code etc. Some tags can be read from several meters away and beyond the line of sight of the reader.