I am trying to create a single formula in one cell that will result in the
following outcomes:

A value ending in 0 through 2 needs to round down to 0 (e.g., $25,402 =
$25,400).

A value ending in 3 through 5, needs to round up to the nearest 5 (e.g.,
$24,174 = $24,175).

A value ending in 6 through 7, needs to round down to the nearest 5 (e.g.,
$18,217 - $18,215).

A value ending in 8 or 9, needs to round up the nearest 10 (e.g., $14,408 =
$14410)