[2022] So one of my friends showed me this pic from one of his games

I love math time.

The odds of AT LEAST 3x 5 costs in a single roll at level 7 is (0.01 * 0.01 * 0.01 * 1 * 1) since order doesn't matter, meaning .0001% or 1 in 1,000,000.

Then from there, the odds of them being the SAME 5 cost get tricky, but for simplicity lets assume all the 5 costs are still in the pool. The first choice doesn't matter (1), then the second and third choices must match (1 in 8, again trickier since its closer to 9/79 then 8/78). So 1 * (9/79) * (8/78) = 1.168% chance.

Multiply those together and you get .00000116% chance, or 1 in 85,600,000 to have 3 of the same 5 costs in your shop at level 7 on any given roll.

EDIT: I did this quick, my math MIGHT be off on step 1, since order gets weird, and it may need to be about 5x higher based on different permutations?