There are three cafes around Kalos that you must pay to enter. Each type of seat you pay for will allow you to talk to customers who will show you a Pokemon for your Pokedex. The 100 price option will show you one Pokemon. The 1,000 price option will show you two Pokemon. The 5,000 price option will only show one Pokemon, but it will always be one that is not in your Pokedex. You can only do each seat once.