Simplify this problem:

1. The neighbor didn't lose a penny, and everyone can understand.

2. The young man took 79 yuan and a commodity worth 18 yuan for nothing.

Then in this transaction, boss Wang's loss is the young people's gain for nothing.

Namely: Boss Wang lost 79+ 18=97 yuan.

If calculated according to 18 yuan cost plus 3 yuan profit * * * and 2 1 yuan, the loss will be 100 yuan.

So, mathematically, it's 97 yuan.

But from an economic point of view, it is 100 yuan.