There are 7 rules of money.
1) You cant spend more than you have
2) You cant borrow from a friend unless youre sure he/she wont ask for it back
3) If you lend someone money, they owe you interest
4) If you want to give someone a gift, make sure its worth more than the value of what they just got
5) Dont buy things on credit unless you know that person will pay you