How much do I tip for a free pizza?!?

We have a coupon for a free Domino's pizza, but how much do we tip the delivery guy?!How much do I tip for a free pizza?!?
15%-20% of what the price would ordinarily be. If you are feeling generous, given the cost of gas, I'd throw in a little extra.
if you are in the US, ALOT. Pizza guys in the Us are the 3rd most likely to get killed at work. in Australia, its not customary but nice....remember the more you pay the less the pizza becomes free lol....maybe a few bucksHow much do I tip for a free pizza?!?
You tip according to what the price of the pizza is without the coupon...I always throw in an extra dollar or two for the cost of gas.
Well 10% of the original pizza cost is generous if he is a nice good spirited guy who delivers it on time with a good attitude.How much do I tip for a free pizza?!?
there probably is still a delivery charge and you should probably give him a few bucks, find out how much the pizza normally costs then do like 20%ish of that
just the usual 20 percent of the original price. which is generous and fair.
The same you always would, it doesnt matter to his pocket whether it's free or not.
I would tip him three or five bucks.
5 dollars is perfect
4 dollars i think is good