At the botton of your game screen is a link and icon labeled, quite simply, "Store". Clicking on this takes you to the main in-game store. This is where you can buy things for real world dollars, which the devs would appreciate if you did regularly. For those of you that would rather spend as little as possible, there are also rewards to purchase with in game currencies that can be earned or farmed.
Let's dig deeper into each of the store sections and see what makes sense to purchase in each one.