bro found my sell quick

The 140 buyer is reselling for $256.24 on Marketplace, which currently is around ~137 Keys: https://marketplace.tf/items/tf2/31272;5;u237

I already suspected that this range was a stretch with the discrepancy between sales being basically 32-140. This settles any doubt that 140 is a clear outlier.

86 flat should be the way to go here. Funnily enough, the median for 32-140 actually ends up being 86, so this flat price works out perfectly.