As of Fall 2006, I stopped tracking T222 prices. 5 years of updates was enough!
This page contains T222 sale prices on eBay and in auction houses over 2002-2006. In 2008, prices for commons generally range from $50 to $250, depending on condition. HOFers are about twice that, with the exception of Alexander and Johnson, which will be 5x-10x higher.
As a representative sample of T222's, this data shows that the most difficult cards in the set are Johnson, Lelivelt, Henry, Lobert and Lee Magee. Not coincidentally, all five of these cards have "15" as their numbered designation. The low-numbered cards are much easier to find, but there are are a few (Sallee, Orr, Huggins, Vitt) that appear less frequently.
Below are results of all T222 auctions on eBay for 2002 through 2005. Conditions of the cards are based on the scans provided, if any.
Below are results of non-eBay auctions from 2001 through 2006.
