One of the best things about Pokémon GO is that it regularly updated with new and helpful features. If you have an Android phone then it would appear as though Niantic is testing promo codes in the Shop which basically allow you to redeem special items without having to pay for them. Promo codes have yet to be properly detailed by the company but they can be used to redeem items such as Poké Balls, Lure Modules, Lucky Eggs, and more.
To redeem a promo code:
- In the Map View, touch the Main Menu button.
- Touch Shop button.
- At the bottom of the screen, enter the promo code in the text field.
- Touch Redeem.