She didn’t pay for it all…. Im not even sure where you got that idea from anyway. She doesn’t pay for the books at all. Her foundation covers the program overhead, but all the funding to actually pay for the books and postage is from smaller local organizations.

https://support.imaginationlibrary.com/article/245-i-was-told-my-local-imagination-library-is-closing-because-of-lack-of-funds-why-doesn-t-dolly-do-something-about-this-or-just-give-them-the-money-they-need-to-keep-this-program-going

The Imagination Library is made possible through funding shared by Dolly Parton and local communities.  While Dolly and the Dollywood Foundation cover many overhead costs and administration needs, the local programs secure the funding for the cost of books and postage.

We partner with a local organization/affiliate that covers the book and mailing cost for a specific geographic area. All other administrative expenses (overhead, selection of books, database, publisher negotiations, and fulfillment of the over 2 million books mailed monthly into 5 countries) are covered by Dolly and the Foundation. By having the overhead expenses covered, all of the money raised locally goes straight back into the community and allows more children to receive books each month.