Eyevet's comments regarding collectors' learning curve re: tests, and their numbers in UNC make perfect sense. The 79 numbering system threw everyone off, and hence the replacements and tests were all quite difficult to find, and now steep in BV.
Supposedly the demand for S/R notes in general are on the decrease.
This is really surprising considering that test notes are a thing of the past. I have seen few to none at the last 2 shows here in Ontario. I saw a RS and 330 $5 in F to VF at the Niagara show. Very high priced with no buyers the first day (perhaps someone did snap it up).
The lower grades seem to be commanding high prices too. Most sellers seem to be ahead of the book in the prices they're looking for.
I think these things go in cycles. Right now everyone is more aware of the G/R (and $5) rarity, so there seems to be a lot of focus on those notes. I recall seeing many test notes on ebay in 2004 but haven't seen many the past year. At the Paris show it was hard to get a decent replacement (let alone a test note). I think the lack of supply will increase the demand (so we might see the BV increase too).
Now that we know there's another E/R test note out there it will be interesting to see if there's a few discoveries. I found a G/R (not a test-- wrong number range) but a nice find nevertheless in a bundle of ratty $2's in Paris. Cost me $3 in F. I think if we keep a vigil out for these notes there may be some happy discoveries yet to come!