The marketplace is not currently sortable by individual Shop, so if you find a Shop that you want to revisit or you wish to purchase directly from your favorite KOL, follow the Shop owner and visit their Shop directly from their profile!
You can also find a specific Shop by searching for a keyword and finding the user or the user's Shop you are looking for by checking the Users, Collectibles, or Shops tab of your search results. From a Shop, you can also easily click to View Shop Owner, and then follow that user to find their Shop easier the next time you look.
Click on the Shop icon at the top of a user's profile to navigate directly to their personal Shop. Once in their Shop, click on the Collectible you wish to buy and follow the "Making Purchases" guide!
Remember to follow the users to easily find their Shop again!