[tw04]

I'm fairly certain the rest of the world would be happy to exchange cash for oil or oil for cash.

[Gibbon1]

Saudi Arabia doesn't have any real way to earn cash except by selling oil. There is the whole Mecca thing, but that's it.

[tw04]

I'm not sure what part of this you're not getting. They're selling off a small stake of the state-owned oil company to diversify how they make money. They'll use the remaining money + new income from the corporations they'll build/buy to import oil. This isn't a hard concept to follow.