Animal Crossing Pocket Camp is an app that you can play on your phone or tablet. It is a smaller version of previous Animal Crossing games. Your character has a campsite in which different items can be placed. Animal friends that are invited to you campsite will interact with those objects. They also sometimes ask you for things, and at other times give you things.
The majority of the interaction between your character and the animal friends runs on barter. Every animal friend you encounter wants something that you could – potentially – give to them if you happen to have it.
There are four (small) locations in the game that your character can travel to in order to interact with animal friends. Each location has something useful that the animal friends want – but appear unable or unwilling to obtain for themselves. Each location has fish, or bugs, or fruit.
When you encounter an animal friend in one of the four locations, a bubble appears over their head that shows what items they want. If you have those items, they will gladly accept them. They will give you some resources you can use to craft items for your campsite. If there is an event going on that involves growing a specific kind of flower, the animal friend will give you some seeds in exchange for what you gave them.
The animal friends don’t have gardens, so they can’t use the flower seeds. Your character has a fairly large garden at their campsite, and needs the seeds in order to complete goals for a current event (and receive prizes). Your character is easily able to catch fish, or bugs, and can pick fruit. The animal friends can’t do that on their own, so they give you something for your efforts.
There is never a point in the game where an animal friend you visit hands you a bunch of Bells (the in-game, easy to obtain, currency) in exchange for the fish, bug, or fruit you gave them. Instead, the game gives you some Bells each time you give an animal friend the items they want. The animal friends at your campsite sometimes hand you Bells for upkeep of the camp.
This has more to do with game mechanics than anything else. Nintendo wants players to have currency that they can spend on interesting items that can be crafted, or to upgrade some of the bigger items that they put in their campsite. Currency makes the game work – but the majority of the animal friends use barter.