There is a Quest Potions in game shopto gain extra Loot Chests for completing quest. With every one potion you will receive 5 additional Loot Chest each time you complete a daily quest.
Average Loot Chest value is about 89 DEC (104 DEC minus value for Legendary and Alchemy potions), according to 
However, as you can see in a screenshot, the price for Quest Potions is 750 DEC in game shop. One can decide that there are is no profit to buy Quest Potions at 750 DEC to receive only 445 DEC in a reward.
But there is a trick: you should buy Quest Potions with Credits instead paying DEC directly. Internal price is 1000 DEC = 1000 Credits. But currect market DEC price is 1000 DEC = 7500 Credits. Here is the profit!
Send your DEC to Hive Engine, swap into HIVE, then buy Credits with HIVE. As a result, you can buy Quest Potion for about 130 DEC only.
445 - 130 = 315 DEC is your profit with every quest!
Nota Bene: You can receive additional 10-15% profit buying 10 or 100 Quest Potions in bulk.