In a pinch instant coffee works. Lately I've been buying the Folgers instant coffee. https://www.folgerscoffee.com/coffee/single-serve/classic-roast-packets

It's nothing to brag about. But it does have caffeine. So theres that.

I have yet to find an instant coffee that made me think it was brewed. What instant coffee is good for is making frozen coffee treats in the summertime.