In my PayPal Button plugin there are certain shortcode parameters that you can use to add automatic discount functionality to a PayPal Buy Now button. These parameters allow you to apply a flat discount amount, multiple discount amounts, discount percentage and buy one, get one free discount.
Buy Now Button with a Flat Discount Amount
In order to provide a flat discount on the PayPal Buy Button simply specify the “discount_amount” parameter in the shortcode.
[wp_paypal button="buynow" name="My product" amount="4.99" discount_amount="1.00"]
Buy Now Button with a Multiple Discount Amounts
In order to apply a certain discount on the first item and a different one on the next items add “discount_amount” and “discount_amount2” parameters. In that case you might also want to allow users to specify the number of items they want to order (Since a Buy button only allows one item by default). You can do it easily by using the “undefined_quantity” parameter.
[wp_paypal button="buynow" name="My product" amount="4.99" discount_amount="1.00" discount_amount2="2.00" undefined_quantity="1"]
When you specify “undefined_quantity” in the shortcode it will prompt buyers to enter their desired quantities on the PayPal payment page.
Apply Discount Amounts on a Certain Number of Items
If you want to provide a $1.00 discount on the first item ordered and a $2.00 discount on the next 3 items, add the “discount_num” parameter.
[wp_paypal button="buynow" name="My product" amount="4.99" discount_amount="1.00" discount_amount2="2.00" discount_num="3" undefined_quantity="1"]
Buy Now Button with Discount Percentages
In order to provide a 20% discount on the first item ordered and a 30% discount on the next 2 items, use the “discount_rate” parameter instead.
[wp_paypal button="buynow" name="My product" amount="4.99" discount_rate="20" discount_rate2="30" discount_num="2" undefined_quantity="1"]
Buy Now Button with a Buy One, Get One Free Discount
You can set a 100% discount on the second item ordered, so the buyer can get one for free.
[wp_paypal button="buynow" name="My product" amount="4.99" discount_rate="0" discount_rate2="100" discount_num="1" undefined_quantity="1"]
In order to receive this discount the buyer will need to buy at least one item.