So, for example, if a price is currently $5.31, the result should be $4.99.
Once rounded, the formula simply subtracts 0.01 to get a .99 value.
The ROUND function can round to the right or left of the decimal point.
MROUND Function
The Excel MROUND function returns a number rounded to a given multiple.
MROUND will round a number up or down, depending on the nearest multiple.