The container is a cube with side length of 8 cm. If the crystals are also cubes with side length of 1 cm, then 8 crystals will fit along one side of the container. Since all the sides are the same length on a cube, we can take the 8 crystals and cube it to find the total amount of crystals in the container.
[tex]8^3[/tex] = 8·8·8 = 512
Each crystal costs 5 cents, so multiply 512 crystals by $0.05.
0.05(512) = $25.60