How do you set up Square for a "pay-what-you-can" environment?

[haally]

We are a non-profit and are setting up a "pay-what-to-can" cafe.  Is there a way to include a suggested donation price per item but, in the checkout process, allow the customer the option to pay what they can (more or less than the list price)?  We can't use a generic donation item because we need to track inventory.  Does anyone have any recommendations on the best way to set up Square for this type of environment?  We're new to Square as well.

[rehlow]

Include the suggested price in the description, but leave the actual pricing as variable so you can set it higher or lower at checkout.