Hello there, I'm trying to get some more water. I take medication that makes me dehydrated. Is there something you mite be looking for in exchange?
I'm sorry to hear about that -- I've been needing water because my child is with me and I can't let them get dehydrated since they're so young. Could we split the other items?
We mite can do that. What do you need more of?
do you want extra firewood if I take extra water?
At the least, Do you think I could get a little extra food if I give you some extra water as well?
yes, that would work for sure
Thats Good, I'm a big guy and like to eat when I'm out and about. 
what if we do 3 water for me, 3 food for you, and split the firewood?
No, that won't work. I told you in the begining I needed some water because of the medication I'm on.
that's right, how about i take 2 water, and you take 2 food?
well I was going to let you have two being you have a kid to look out for. But i atleast need the one. So how about I get one water you get two. Then I get Two fire wood and two foods?