I don't see any reason to really exclude 55 from the range here.

As far as advice goes, I wouldn't have ranged this 49 - 50 keys with your logic, you need to round sales to the closest key above 10 keys

Source:

https://forums.backpack.tf/topic/6033-rules-for-unusual-price-suggestions/

"

Rule - for all unusuals below 5 keys, rounding to the nearest 0.05 keys is required. No other decimals are allowed.

Rule - for all unusuals 5-10 keys, please round to the nearest 0.5 keys. No other decimals are allowed.

Rule - for all unusuals above 10 keys, please round to the nearest whole key

"

So following your reasoning regarding sellers floating around 49/51 keys, and using the 2 49.5 key sales to range here, it would be 50 flat

I think 50 - 55 keys works for the time being give current sellers at 56 keys+

Of course, wait for a mod to respond :D

Excellently made suggestion, keep it up.

Couple final notes just from me:

Actual item history for first item - https://backpack.tf/item/278285954

Sale 2 is rather dubious

Strange Terror-Watt Galvanized Gibus instead of non strange

https://backpack.tf/item/6678646002

https://backpack.tf/item/9374597855

Neither history seems to match so I wouldn't say concretely that was the sale

Sale 3:

https://backpack.tf/profiles/76561199084784906#!/compare/1607558400/1607644800

It is now outdated, here is the correct "buyer's" link for the trade

Sale 4:

You cannot say for sure that sale was 49.5 keys, I would just say it was untraceable

Sale 5:

You yourself paid 55 keys for the hat, a pure sale certainly seems to warrant a range of sorts

So from the above:

We have a sale at 49.5 keys, rounding up to 50 keys

We have your pure purchase at 55 keys

I think 50 - 55 keys is a fine call here now