I am trying to build or find an on-line instant quote calculator

the formula I am trying to calculate is

49 for the first 35 items

0.85 each item thereafter

user inputs total amount of items eg 400 items

400 items - 35 = 365

365 * 0.85 = 310.25

310.25 + 49 = 359.25

Total Price 359.25

Then the total price 359.25 / 400 to give the price per item 0.89 (to two decimal places)

I've found several on-line calculator builders but nothing that can handle this sort of variables.

This script is the closest I have got but my maths is terrible and I cant seem to edit the code correctly http://www.dynamicdrive.com/forums/s...ote-calculator