There are a couple ways to go about this.
The simplest way to do this is to create a field called unit price and enter exactly what you'd like displayed into the field.
A more complicated way to do this would be to calculate the output in a spreadsheet program like excel and use the bulk import tool in the app to put the output into the same field described above.
The third way would be to create custom template logic which would take each component of the equation and output the result when the product is viewed. This is effectively the computed field you were asking about, but it requires custom template coding to accomplish.