The Extended Cut of Order Discount covers tiered discounts.

It is more of different prices for larger quantities than a % discount - here is an example link -
https://mailthings.com/circle_tabs.php

If you don't want to use a percentage and I'm assuming they cant all be like 2$ off, you might need to make multiple prices in your product table. ProductPrice, Discount1ProductPrice, Discount2ProductPrice etc. Then just dlookup which price to put depending on the quantity they bought.

I would set this up similar to my example (see screenshot).

HI Carol, I would suggest some kind of lookup table.  If a fixed discount isn't used, or if the rules of the discounts are irregular in general, and if those rules and prices are subject to change, then I would consider setting a price for each individual unit so you would be able to modify them however you like, when necessary.  The lookup table would look something like, using your example from mailthings.com:

ProductID    OrderUnits    DiscountUnitPrice
P1000        1             $22.50
P1000        2             $21.50
P1000        3             $21.50
P1000        4             $20.50
P1000        5             $20.50
P1000        6             $20.50
P1000        7             $20.50
P1000        8             $20.50
P1000        9             $20.50
P1000        10             $19.50
P1000        11             $19.50
P1000        12             $19.50
P1000        13             $19.50
P1000        14             $19.50
P1000        15             $19.50
P1000        16             $19.50
P1000        17             $19.50
P1000        18            $19.50
P1000        19            $19.50
P1000        20            $17.00
P2000        1             $29.50
P2000        2             $28.50
...
and so on.

During order entry, it would be straightforward to use DLookup() to look up the unit price for the units ordered:

   =DLookup("[DiscountUnitPrice]", "PriceLookupT", "[OrderUnits]=" & IIf(OrderUnits > 20, 20, OrderUnits))
  
Note that the lookup table above only has prices for up to 20 units (which you can change to whatever you want).  That is why I use the IIf() function above.  If OrderUnits is greater than 20 units, treat it as 20 units and return the price for 20 units.

The database is currently in Filemaker Pro ' when I enter the stock number and then the quantity, the correct price for that quantity automatically comes up on the entry form. I am just trying to duplicate that simplicity for my employees. Problem with Filemaker is the database I have is 15 years old and the software won't load on new computers ' updated version is expensive. Hoping I can re-do it myself in Access.