Not sure the pricing structure, but I remember office depot having an advertisement, it was probably like "As Low as $6" per pay period. Ths site says $70 a month but that's probably the minimum for the whole company. Then per check fees.
A good example is working remotely in another country. The US does not allow foreigners on a visitor visa to work remotely. It's a bit of a gray zone, since if you fly into the US for a business meeting, that's not regarded as "working in the US". But flying in for 1 month and working remote the entire time is.
Same with California income. Working in Nevada and then decide to work remote from California? That's CA income and taxable by CA. But of course people rarely even mention they're working in another state and rarely pay taxes owed.
Imagine Apple USA being taxed by New Zealand, for example. That's the main reason Apple employees are employed by Apple NZ