Old and overpriced. Also quite the difficult endeavor to price.

Sale 1:

http://backpack.tf/profiles/76561198058717168#!/compare/1471651200/1471737600

Sold with DBD Vintage Tyrolean + 12 keys for a Sunbeams Data Mining Light. Bulk, not using.

Sale 2:

http://backpack.tf/profiles/76561198084976847#!/compare/1472860800/1472947200

Fedora is outdated and can't find a mini, but sale is bulk anyways and not using.

Sale 3:

http://backpack.tf/profiles/76561198125551756#!/compare/1476144000/1476230400

Sold with 3 keys for a Spec KS Aussie Sniper. Using 29 for Sniper

x + 3 = 29

x = 26. High end.

Sale 4:

http://backpack.tf/profiles/76561198063070081#!/compare/1473033600/1473206400

Sold with for 4 keys and a Circling Heart Football Helmet. Current prices would put this at 18 keys, seems a little like an outlier. Not using.

Sale 5:

http://backpack.tf/profiles/76561198146911078#!/compare/1475798400/1475971200

Sold for 12 keys + Australium FON. I don't think the keys on the top are related to the sale.

x + 12 = 24, using as low end.

I'm not really sure about this suggestion. There are still lots of sales out there but not all might be usable. If others want to come forth with sales and suggestions, feel free