ORBS that you earn in-game are used to spend in the SHOP. Orbs are awarded from random loot drops and Sector completions or can be purchased in large amounts for when the item you've been waiting for appears in the SHOP.
ORBS are the currency used in-game to purchase items from the Shop. These are random drops that can be obtained from loot you receive from killing monsters or Sector Bosses.
Another way to obtain ORBS is by completing Weekly and Daily Bounties. Depending on the activity, they will reward different amounts of ORBS, and the Weekly Bounties will reward much more.
ORBS can also be purchased in the In-App Store, but this is completely optional.
The SHOP allows you to use ORBS to purchase in-game items that include nearly everything in the gamee that can drop as random loot. The SHOP is dynamically updated daily, and its stock is refreshed from the backend services of the game itself.
Depending on the occasion, it's also possible there will be holiday sales active in the SHOP.
When the inventory of the SHOP has been updated, a red badge will appear on the Main Menu letting you know to check out the latest loot available to buy.