Most credit unions I have been in do not have a minimum for basic checking. You yuo want some perks then you may end up losing money due to minimum balances, but they don't apply this to poor members because you specifically need a large amount of cash in the accounts to make the switch.
The illegality of credit unions (non profit money institutions or approximately banks) is equivalent to a regressive tax in the amount that the big banka in the US earn from these petty fees. Why would you not want a non profit bank? That case is so clear that it is only the entrenched interests of the super rich that have prevented it.
Note: they are not illegal, but you can't just make a general credit Union for everyone and compete with banks. Why? Well you would certainly kick the banks to the curb, which is exactly what their powerful leaders don't want.