:) Hi there, would you like to negotiate on the camping supplies with me?  If we negotiate, we both have a good chance of getting more of the supplies we need!🙂🙂
Ya I'd love to! What I really need is food and water because I have ten kids! 
Oh wow, that's alot!  I was needing food and water because I'm a large guy and currently dehydrated already.  My doctor says I need at 3000 calories a day just to maintain my weight and desperately need the water to overcome the dehydration.  What do you propose?
Wow that's a lot! Do you need food or water more?
Well, since I'm dehydrated, I'd say the water.  Sounds like you need the food more for all those kids.  How about you get 2 food, 1 water and 1 firewood.  I'm camping in Alaska and it's really cold so could use the firewood.  That way, you get 2 food for your kids.  
Can I get 3 food and you get three water and one firewood?
Well, I think I really need at least 1 food or else I'll starve!
But Water is your most essential item! If not that how about two food one water and two firewood for me?
But you need the food for all those kids and I need the water for my condition and the wood because it's so cold.  How about 3 food for you and 1 wood and I'll take the 3 water and 2 wood?
Sure
Ok, great!  Let's do it!