They moved around (though the cowboys were herding cattle, whereas the Native Americans were following the buffalo). They cared for the cattle (eg by bog-riding and from line-camps) in a way similar to the way Native American dog-soldiers cared for the buffalo.
Capitalist economic relations were considered free because private individuals or businesses were given the freedom to choose what goods and services they would want to market or produce, where they would want to invest, and at what prices should they set on their goods and services, depending of course, on the supply and demand of the economic market.