@arm_barbarian honestly if it's a situation where that is happening you should expect to overpay in case there is no change, so if you just stack a few 20s that will be good enough.

Trying to optimize for "I don't want to lose money" just makes keeping the emergency stash harder.

In emergency situations the pricing of things is much different and everyone should think about it now. You don't want to be buying anything you don't absolutely need before the emergency is over and you should expect pricing to be based on absolute supply and demand.