I’ve gotten a few of these–they are evidently partially publicly funded, which, as this e-mailer points out, makes sense:

My admittedly rudimentary understanding of presidential libraries is that only the Archives aspect of the library is, in fact, publicly supported. For these libraries to be a legitimate destination for researchers, and any good at all, they incorporate the official government documents from the administration, and the archivests that go along with that. I don’t think we would want the nation’s archives doled out to a private group for whatever they might do with them.
But most of the swank you see at a presidential library is “private.” Tax exempt foundations raise funds from the administrations supporters, etc., to build the halls, polish the marble, run the little TVs with videos, and so forth.