Ceiling( your_price_field / 5 ) * 5
Note: the Ceiling function may not work the way you want for negative prices.
One option is to use a Case statement in the calculation to test each field in the formula ( not IsEmpty(…) )
Rounding up is working perfect
Having a bit of a problem getting the Case statement to work with a 'not IsEmpty' formula. How does this exactly work when I want the calculation field to be empty if one of field1, field2 or field3 is empty (fx: field1 + field2 - field3 = calculation field)