The Old Improbable Island Wiki

Hats, worn on the feet in most civilized societies, are a way of flaunting wealth that would've been confiscated after a DriveKill. Hats are bought at Deimos' Haberdashery ^1)2)3)4)5)6). 1000 req will buy you a size 1 hat. After that, each next sized hat costs 10% more than the last. Thus the formula is log(cost / 1000) / log (1.1), rounded up. You can upgrade a hat (though Deimos requires you to spend at least 10% the current value of your hat to do so). This is where all that req should go before you kill the Drive.