1. Need
   1. video
      1. bartering (trade)
         1. pros
            1. have
            2. have
         2. cons
            1. clumsy
            2. valuable
            3. desired
      2. money
         1. Pros
            1. buy
            2. want
2. functions
   1. exchange
   2. standard
      1. Ray
   3. store
      1. coat
3. characteristics
   1. stable
      1. scarce
   2. accepted
   3. divisible
   4. SAD