Requirements for the Subtotal A subtotal is the total amount for the products before taxes and shipping and handling charges are added. The subtotal for a transaction must be greater than zero. If the subtotal is less than or equal to zero, PayPal declines the transaction. To calculate the subtotal, PayPal does the following: 1 Identifies the offers for which the product code is not handling_only, shipping_and_handling, or shipping_only. 2 Multiplies quantity * amount for each offer identified in step 1. 3 Adds the values that were calculated in step 2. Example 1 Offers That Cause PayPal to Decline a Transaction offer0=amount:10.00^quantity:1^product_code:Beverages^product_name:Fancy Cola^merchant_product_sku:B4859^tax_amount:10^product_description:Description for Fancy Cola! offer1=amount:5.00^product_code=shipping_only offer2=amount:10.00^quantity:1^product_code:coupon^product_name:Discount^merchant_product_sku:D1000^product_description:1000th customer discount