To get to the Mystic Shop go to level 3 in Campaign Clash (from Ancient Relic) and click on the blue caslte that says "click." This caste also appears at level 13 if you can get that far into your campaign. It may appear later on as well (I don't know as I've never gotten past 14). Each shop has a random set of 6 things you can buy for either Jewels or Gold.(Quem é português como eu :D clique em traduzir)
What's for Sale? Edit
Many of the for sale options are Hero Shards (HS)--puzzle pieces that once completed result in your acquiring that hero. The best heroes require up to 1500 HS, so it will take some time to get enough to acquire them. However, Blitz Bomber requires only 150 HS so he could potentially be earned in a month or so. Also for sale are Coral experience eggs, Gold experience eggs, extra mystic points and souls.
Epic Heroes: 1 Shard = 90k gold or 20 gems
Mystic Crystals: 100 Mystic crystals (60k); 300 Mystic Crystals (180k), 900 Mystic Crystals (120 jewels); 3600 Mystic Crystals (480 jewels)
Other: 30 rings (270k); 100 rings (200 jewels); 3000 souls (200 jewels), 15000 Souls (1000 jewels); Purple Experience Card (96k);
Heroes that can be purchased with Hero ShardsEdit
Renee Ven (1500 HS), Abyss Demon (1500 HS), Pan Goli (1000 HS), Pounder (850 HS), Blockhead (750 HS), Hydrasaur (750 HS), Dark Rider (750 HS), Demon Slayer (750 HS), Skull Mage (450 HS), Glory Priestess (550 HS), Aire Elite (400 HS), Savage Chief (200 HS), Blitz Bomber (150 HS)