Most of the US is at-will, employees can be fired for no reason or any reason as long as there's no breach of relevant federal statutes (Equal Pay Act, Civil Rights Act, Age Discrimination in Employment Act, Americans with Disability Act, …) — the latter being why employees are generally fired with absolutely no reason provided just to avoid any possibility of status breach.
That means for most firings there is no legal recourse, because there is no legal labour protection.
Most of Europe is very different on that point, you can't fire somebody just because you feel like it, and there are a number of labour-focused courts which tend to have a very bad view of companies trying to break or skirt labour laws.
It's not a question of money, it's a question of laws, or the lack thereof.