Well folks, if you like to code your own stuff, then there are a few options for offering discounts. If coding is not your thing, then you need to use a 3rd party shopping cart. For example this one is quite easy: http://www.e-junkie.com/ and there are lots of other carts out there.
As for coding for discounts and coupons, you can do this thru scripting and/or use the PayPal HTML Discount Variables. Regardless of the method, you need to manually code your item buttons as the online button creator does have it's limitations. The exception would be if you have some very basic requirements, then it's possible to use the online button creator.
Tip: To use the Item Code Discount Variables with "hosted" or "encrypted" item button code, you need to modify button code using the "Advanced Variables" in Step 3 of the online button creation process. Look for the text box near the bottom of the page. There you can insert extra variables. For example, you want to offer your customers a 10% discount on one particular item regardless of the quantity of that particular item. Simply insert the "discount_rate" and "discount_rate2" variables in the text box. Just enter:
discount_rate=10
discount_rate2=10
There's no HTML extras, just the name of the variable, an equal sign and the value.
Tip:
Here's some important stuff to be aware of. The Discount Variables listed below are intended to work with Buy Now Buttons and Add to Cart Buttons. They only apply to the item they are associated with, "not" the entire shopping cart. This means that you can "only" apply a Discount to an individual item and they do not apply to Taxes or Shipping.
discount_amount
discount_amount2
discount_rate
discount_rate2
discount_num
Tip:
The following Discount Variables will only work with the "Upload" Method.
discount_amount_cart - Applies to entire cart. **
discount_amount_x - Applies only to the individual item.
discount_rate_cart - Applies to entire cart. **
discount_rate_x - Applies only to the individual item.
** Note: These variables will be ignored if you are including any individual sales tax amount or rate in your upload code. This is because the sales tax needs to be calculated after the discount is applied to your items therefore, the discount is applied to the item Subtotal, not the Total. In addition, the discount does not apply Shipping.
Having said all of that, this site has a tool that may help:
http://www.webdesignetc.co/generate-paypal-discount-codes/
And you can find examples here:
Coupon Codes: http://ccaples.com/index.php/basic-scripts/examples-i/coupon-codes
Using the Discount Variables: http://ccaples.com/index.php/basic-scripts/examples-i/coupons-using-paypal-s-discount-variables
Quantity Discounts: http://ccaples.com/index.php/basic-scripts/examples-i/quantity-discounts
