In Pokemon Pokopia, there can still be shops around and items to buy even without humans, with rebuilt Pokemon Centers being one of the first returning places of business. However, since these are Pokemon and not people, the buying and selling process works a bit differently. It’s basically a bartering system.
How do I buy and sell items a Pokemon Centers in Pokemon Pokopia?
This can come up as a feature as soon as the Withered Wasteland Pokemon Center is rebuilt. After that is operational again, a Pokemon capable of running a shop (like Hitmonlee or Clefable) might show up behind the desk. When they do, a number of random items like Pokemetal, materials, and furniture will show up on the counter. If you approach one of these items, the character there will offer a trade and suggest a price. For example, Pokemetal will always be 2,000 points, regardless of the vendor. You then need to trade items from your inventory to make that happen. A gauge in the center will show a sad face if you’re coming up short and a happy one if you can meet the asking price. Once satisfied, you can press + to confirm, then choose to trade and finish the deal.

One of the best items you can “sell” at a Pokemon Pokopia Pokemon Center when trying to shop is a spare fossil. From what I’ve seen, these tend to be worth 1,000 points each. Since the more expensive items there usually end up being around 2,000, this can get you to the goal with very little effort and helps you get rid of a duplicate item you don’t need anymore once you’ve already reconstructed the habitat associated with it.
However, this is also a great way to get rid of extra blocks you collected during the terraforming process. These might only be worth about 10 points, but it isn’t difficult to find yourself with 99 of an item after you’ve done a lot of work clearing out an area.
Pokemon Pokopia is available for the Switch 2.