In Handbid you have the ability to add a discounted or credited amount to a purchasers invoice.
When you go to pay an invoice in Handbid you will want to go to INVOICES > ALL > then select the bidder's invoice you want to charge. When selecting to pay an unpaid invoice you will see the PAY NOW button. Click on the PAY NOW button this will then display a break down of different ways to apply a payment. View the images below for a breakdown of that process.