6 month old price, counter suggestion. Just going to copy my comment from the other suggestion, look there if you want more context.

http://backpack.tf/vote/id/54cdb003b98d8855628b47fd

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Sold for Australium Grenade Launcher (~23 keys at time of sale, buds were 11 keys at time of sale) = ~1.8 buds but the B/O was 17 keys so the sale can only be valued at ~1.5 buds using that same bud price.

http://www.tf2outpost.com/trade/24217803

http://backpack.tf/profiles/76561198078919967?time=1419062400

Your first sale is also wrong, it sold for 1 bud + 3 keys + ~2 keys in sweets

http://backpack.tf/profiles/76561198062802524?time=1421654400

The two sales give you a flat value of 1.4 buds.

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