To give you a easier to understand example:

Suppose you want to buy a car that another member of the community built and is selling.

The "price" doesn't exist, so how do you know "how much" are you going to pay for it?

You ask the network (the computers), and they tell you "this car costs 1420 JOE tokens".

You know perfectly well how much each JOE token costs to you, because you issued them and you redeem it regularly! They cost you each one hour of hard work.

The tokens don't go to the former owner of the car. Instead, on YOUR account you get -1420 JOE credits.

On the other hand, the former owner of the car gets a positive amount of HIS tokens credited, in a proportion calculated automatically by the network, based on a simple algorithm (consensus rule) that compares different token issuance smart contracts of all members of the community.