Resuggesting after discussing with polar.

Sold for Ghosts modest (9.2) + SF Sticky (0.9) + 19 buds + 4 keys (0.3) ~ rounding up to +/- 30 buds:

http://www.tf2outpost.com/trade/23446667 - "I'd need at least 30 pure" - seller was willing to take 30 pure buds.

http://backpack.tf/profiles/76561198014627995?time=1415520000 - after

http://backpack.tf/profiles/76561198014627995?time=1415347200 - before

Two sales is not needed:

http://forums.backpack.tf/index.php?/topic/6033-new-unusual-price-suggestion-guide-the-cheat-sheet/

Exception 1: High Tier Hats

Sales for high tier hats (>20 buds) can be based on a single sale if there are no other sales in the last 3 months. Estimations can be made for unpriced / outdated parts of that trade as long as reasonable estimations are provided.