How can I measure if I don't have a scale?

I just bought ground chicken meat and would like to make a patty.  I was wondering what would be a decent size and how could I measure without having a scale?

A 3 - 4oz portion of meat is about the size of a deck of cards or the palm of your hand.  Kitchen scales are very cheap and save a lot of guessing.  If you're on any kind of weight-control plan, they're well worth the investment.

Yeah you can get a kitchen scale from wal-mart for like under $10.00.

They are so worth it.

I got mine at target, it's about half an ounce off but for the $4 i paid for it I have to say it's totally worth it. In fact I think I'll be getting a digital one shortly, it's the best tool in my kitchen.