Hello there. What is your most valuable item you would like?
I would like the firewood please. 
How much would you need?? I unfortunately am in need of some as well.
These will be helpful for my trip. How about I take 2 and you can have 1? I will give you a good deal on another product if you accept. 
It has rained a lot in the area I will be going to, so the availability of dry wood to scavenge for will be difficult. Do you know of any techniques to dry out wet wood?
Yes, you can place it in the sun during the daytime hours. Should work. 
That makes sense. What is your need for food?
I don't need much. How about you take 2 and I have 1?
That would be very helpful! Because due to the high amount of rains I believe the poisonous mushrooms will be thick, so to be safe I think having extra food would be wise.
Yes, I believe that is good. Now how about your need for water?
I would be willing to give you 2 and I take 1. There is plenty of rain water to collect and a spring nearby.
Sorry, I am going to need a lot of water. It has been really dry here. Can you collect a bit more water and give me 2 so I am not too thirsty while camping?
Yes, I am willing to give you 2 and I will take only 1.
Oh, that is very kind of you.