If you were going to base your Degroot mini with sellers, you should've just taken 45 flat.

Either way, here's some actual sales for the Degroot:

Sold for Orbiting Fire Tough Stuff Muffs, a Circling Peace Sign Triboniophorus Tyrannus and 1 Key

http://backpack.tf/profiles/76561198050518375#!/compare/1492041600/1492128000

Sold for 40 Keys

http://backpack.tf/profiles/76561198012473875#!/compare/1491091200/1491177600

Sold for a Death at Dusk Tavish Degroot Experience

http://backpack.tf/profiles/76561198132176657#!/compare/1491523200/1491696000

Sold for a Dead Presidents Killer Exclusive(45.5 Keys, round to 46)

http://backpack.tf/profiles/76561198259500466#!/compare/1491696000/1491868800

Sold for an Eerie Orbiting Fire Cosa Nostra Cap and ~6.5 Keys in Sweets

http://backpack.tf/profiles/76561198018823628#!/compare/1487462400/1487548800

Sold with a Strange Festive Pro KS Knife for a Purple Energy Whoopee Cap

http://backpack.tf/profiles/76561198122531258#!/compare/1487894400/1487980800

Probably better used for that.

Sold for 36 Keys

http://backpack.tf/profiles/76561198112279227#!/compare/1487894400/1487980800

Sold for a Circling Peace Sign Ol' Snaggletooth and 30 Keys

http://backpack.tf/profiles/76561198083030915#!/compare/1487894400/1487980800

Sold for 49 Keys

http://backpack.tf/profiles/76561197995194055#!/compare/1491523200/1491609600

Unless mentioned otherwise, every hat here will need a mini suggestion. Feel free to resuggest once you've come with a proper valuation for the degroot.

The Tavish got suggested at 45 Keys: http://backpack.tf/suggestion/5907704be338772f8005298f

Feel free to resuggest at 45-60 here.