Yeah, you're right since we have no time to elaborate on the value balance for each shop item. As a result, we make it a pretty difficult puzzle actually XD.
To beat dice king, you need to try to get Reproduction Dice and Dice chance by focusing ( without paying coin ) as much as possible. And then buy Soros and Deamon at the same time. Finally buy all Reproduction Dice and Dice Dice before you run out of all chances, then you may beat the dice king!