Not aware of any cracks. I use the felddy image on my Unraid setup and the first window on a fresh install asks for the license. Same goes for when I run locally on Windows. I'm sure there's a crack out there, but I'm not aware of it.
All I can offer is my full endorsement of Foundry. It's worth the money. If $50 is a bit steep at the moment, I think they do offer a small discount with an anniversary sale each year. Not sure when that is exactly.
Switched from paying Roll20 an annoying monthly fee and it's more than paid for itself now. There is even a tool floating around to export active Roll20 games for use in Foundry. I remember it being pretty inefficient, but better than starting from scratch.
There could be one more to differentiate engineers from architects. Do you like to solve problems (engineer) or create them (architect)? Fun flowchart!