The Market Unlocks after completing Chapter 2. In the Market you can use Gold and Diamonds to purchase Badges, XP drinks, and Hero Chips. The Market refreshes 4 times a day.
There are other shops where you can spend game tokens. For example, you can spend Arena Tokens in the Arena Shop to purchase Badges, XP drinks, and Hero Chips. Unlock more item slots with Guild Perks.
There is a Badge Bazaar where you can buy badges for your Heroes using Badge Tokens.
All purchases from the market are final and cannot be reversed or refunded.