I've an opportunity to create a store offering zero cost (ie free loan) resources in an educational setting. A central school holds significant inventory of different 'resources' that other schools can check-out, like a library.

theyll deal with loan duration separately.

how would you suggest we approach the free payment route?

I think I've been able to answer my own question.

i enabled the Cash on Delivery plugin and created an item of zero price.

All processed without a hitch.

so now I know!