Is it OK if I demand money over favors?
What makes you want money so much?
I regard money superior to favors. I make the rule, not anybody else.
If someone is offering you something, you should not ask for money instead. It will come across greedy and ungrateful.
Sorry, but I want the cash on the barrelhead -- forget about the favor bullshit.
You will soon exhaust the list of people offering favors, money, or anything else with that attitude. You should appreciate and cherish the good faith offers of help from friends. Real friends aren't easy to comeby.