They probably about to ban me for this but for new players or anyone don't waste you're units on these

, they will make it look like you are near to pull the champ but it just rolls over to gold. Now unless you're in need of gold these crystals are great for that but if you want the character don't waste you're time he ain't even that good, unless you have 10,000 units for the 5 star one to gamble and 6 star 30,000 units go for it.