Require a formula for Excel Spreadsheet

Hi All,

Can anyone give us a formula to use on Excel for the following;

First 500 Items paid at $ 0.80

next 500 Items paid at $1.00

next 500 Items paid at $1.20

rest paid at $1.40

So if I have 743 Items, I would be paid $643.00 and if I had 2054 items, I would be paid $2,415.60.

What I'm looking at is to put the amount of Items into a cell to give me the correct dollar figure.

Cheers,

Robert1966