Step AWAY from the application!
Seriously, the last thing you'll ever need if you're interested in life of 'financial freedom' is a credit card.
"Credit" as you use the term, is largely an American myth.
I'm a fiscal conservative (GASP!) and truly believe in living on less than you make.
Did you know that you CAN get a mortgage without credit cards in your name? That getting cards with high limits will actually HURT you when you apply for a mortgage?
Did you know that paying your rent early or on-time, and staying current or early on utilities HELPS your "score"?
So...my answer is "NONE!!!!!!!!!!!"
You don't need them.
Rarely do people "pay them off religiously" every month. And that is how it all starts. Pretty soon your minimum payments equal so much that you can't afford a house payment anyway.....
You sound young. You're a credit card "virgin" and best to remain that way.
The "rewards" are a sham. People spend something like 27% MORE when using credit cards as compared to using cash....so sure--they can give you 5% back without batting an eye.
Credit card companies aren't in business to help people, they're in business to make money. Lots of money. And they do.
Good luck!