Backpack.tf's unusual prices are stored in Keys, at least the number of keys represented in a bud at the time of the suggestion. When the bud goes for 24 keys, and if the unusuals' price suggestion is accepted @ 3 buds, it's technically 3 buds x 24 keys = 72 keys.

Now that the value of buds has dropped so much, to 18 keys on bp.tf, therefore the value of the unusual rose gradually in terms of the bud value on bp.tf. Therefore the value of the unusual in buds rose with this calculation: 72 keys / 18 keys per bud = 4 buds.

Since the trades are open for several months and the value of buds fluctuates, which may hint others about the potential TF2 economy crisis, it's common to see unusual traders still have their B/O set to 3.5 buds most likely based on the > 3 buds price when the buds were high against keys.

Lots of people took this low bud value's advantage to buy unusuals at lower price, because buds are cheaper now.

Another Scorching Mining Light: http://www.tf2outpost.com/trade/14884879

Some decent offer i guess: Burning Festivizer for the Mining Light

: 3.2 buds ~ 3.5 buds = ~3.35 buds x 0.9 unusual overpay = ~3 buds

Anyway, as new hats and new effects join the party, buyers get more choices. This will average out the prices of other normal looking hats. Upvoted.