With small sums ($5), it's too easy to slip into the same mindset after your buddy offers you a beer (since it's basically paid for)

In high school we combatted this with a $20 buy in. Now we do a $50 buy in. Sure, it kinda sucks to lose. But the money is just going back to your friends, and a dinner + drinks out on the town is likely to cost the same. Even when you lose you still had a fun night. And when you win it's even better!

Of course, we are only playing once every few months.. so it's really not a big issue financially.