The potentially confusing factor is that the organization's cost to acquire the items applies only to this single provision, having to do with providing low-cost items bearing the institution's name or logo, provided in return for a gift of at least a minimum (inflation-adjusted) amount.
In all other quid pro quo situations, the benefit is treated at its Fair Market Value (FMV), and not at the organization's cost.
(You may be interested to learn that this low-cost item provision has its roots in a slightly different context, that of an organization sending out some item as part of a gift solicitation, in anticipation of receiving a gift, the predecessor to the current ubiquitous practice of sending out return address labels with the solicitation, perhaps. The concern was that, if the charity sent out something valuable enough, a gift in return wasn't necessarily entirely charitable, so the tax code limited the value of what could be sent out in this sort of enticement. That was later applied to the now-more-common sequence, where we receive a gift and send a low-cost item in response. That is also why this one provision references a different part of the tax code than where we find most of what governs charitable contributions.)
My US$0.02 worth; the usual disclaimers apply.
Alan S. Hejnal (he/him/his)
Data Quality Manager