I have only been to Vegas once, and I expected to lose $100 bucks (I did too lol). But I would usually just sit down, bet a penny until the girl walked up, get a beer, give her a dollar and leave.
I did that a lot at the bars too with the electronic poker machines. I tipped the guy 5 bucks one time for 2 beers because I won $5.
I easily drank $200 worth of beer on that trip for free (excluding tips)