The premium currency in Shadow Era are Shadow Crystals. They're used mainly to purchase pre-constructed or booster card packs; however, they may also be used as an entry fee for tournaments.
Promotion[]
On October 6th, 2011, the $2 million promotional event was started as show of appreciation to all of the loyal fans of Shadow Era. By visiting the event page, you can claim a free 100 to 200 Shadow Crystals for each account. {C} It´s the most of Cost game the world
Purchase[]
Purchases can be made in-app on mobile devices or through various checkout services on the computer. Bonuses are given based on the purchase amount; so the more you spend, the greater the bonus. For example, spending about $5 USD buys 600 Shadow Crystals, but spending about $50 USD gets you 7500 Shadow Crystals.
Earn[]
There are various methods to gain free Shadow Crystals effortlessly. One such way is using the Referral system. You're also awarded 25 Shadow Crystals whenever you level-up.
Income can also come from offers provided by third-party companies. To do these, on the Merchant screen, click/tap on your Shadow Crystals, in the bottom-left corner, and then tap on the Earn Crystals button. On the computer, offers are provided through SuperRewards. Some are easy and yields a good amount of Shadow Crystals. An example would be signing up for a free trial on Netflix, which can earn you about 1400 Shadow Crystals. Do note, some offers may spam you with advertising so be very wary when giving out any contact information.