Once when pokemon pop up and we can store em at pc, some items will be added to the mart in order to evolve some pokes like eevee (that has already benn decided) but one more thing should be added. As people will buy a lot of pokeballs and items as there will be able to catch all pokes they can, the money will run out sooner or later. A solution could be to earn some money killing wild pokes and more money killing pokes from trainers (the stronger the owner trainer is, the more money you get) so people can make sure they can buy all the things they nedd. The amount of money shouldn't be so big in order not to make it too easy to get all the things too quick. Remember that this updates should be added at the same time of the main ones or later.