What does the Weapons button do?
This takes you to the weapons offer screen. Here, you will be shown various weapons that are on offer.
You can find more information on the shown weapon by tapping the "i" button on the left.
You can purchase the shown weapon by tapping the Gold button on the right.
You can also tap the arrow buttons in the bottom corners to scroll through the different weapon offers.
Finally, tapping any of the weapon types at the bottom will take you to the Weapon screen for the type that you selected.