With a smallish playerbase, it's become harder and harder to find parties willing to split the 1800e cost for a shadow key.
With a 4 player party, the cost is 450e per person, which is a decent amount for one person to pay when running a shadow lair.
Seeing as though 450e is an acceptable price for one person to pay, why not make it the same for solo, duo, or trio runs?
What I propose is that four different shadow keys be made available for purchase from the supply depot.
A solo shadow key that costs 450e
A duo shadow key that costs 900e
A trio shadow key that costs 1350c