If I overheard you saying your were too pretty to buy your own drinks, I would consider that you think you're probably too pretty to be a friend of mine, as I'm an average-looking person and I do buy my own drinks. It's just off-putting. And if someone says "you owe me a drink" you just laugh and walk away. There's certainly no need to respond with "I don't pay for drinks! I'm too pretty to pay for my own drinks."

Do you hear how that sounds?

You can be friendly without making comments about yourself that make you seem like you think you're better or more special than others. As people about THEMSELVES.