Suppose you need to get your house painted. You register with a barter Web site and want to offer your car cleaning services to someone who will paint your house in return.

Nowadays there are a lot of services, apps, and websites, on the internet, even just with our cellphone, we could find any service.

For example:

We can change our service, in this case, we need a person, who needs something like a car wash, we must wash his car while he paints our house.

We can change almost everything, services, objects, experiences, knowledge, even big things like a house or a car.