Use the "Formula Is" option instead of "value is".
You can then enter a formula such as Inventory::Status = "Sold".
Is there also a way that I can change Inventory::Rental Status to "INACTIVE" when I select SOLD or BROKEN on the Inventory::Status field?
There are several ways. An auto-entered calculation can change the value of Rental Status when the value of Status is changed is likely the easiest way to set this up.
If ( Status = "Broken" or Status = "Sold" ; "Inactive" ; Self )
and clear the "do not replace existing values...." option.
Self preserves the current value of Rental Status in cases where Status is not Broken or Sold.
Cool. Is there a way I can add to that calculation by making it so that if something is "FOUND" in Inventory Status that Rental Status is "ACTIVE?
Case( Status = "Broken" or Status = "Sold" ; "Inactive" ;
Status = "Found" ; "Active" ;