Zero Dollar Requisitions for Services

Hello,

We are on V12.1.3. I have been doing some research and found a couple of community posts that mentioned you are not able to do zero dollar non-catalog request requisitions. However, we are able to do them if the item type selected is billed by quantity (services or goods). If I try to test a service billed by amount, I get the error "Amount must be a positive value." While this makes some sense, our organization is getting some donated service agreements that we want to account for and not charge a dollar value to. What is the best recommended