The answer to this is important in order to properly size the effort. If the goal is to impove the business efficiency of the store, then it should be seen from ROI stand-point. Even the fellow customers/rummaggers could be engaged with a right incentive and tools. Otherwise, the next estate books container shipment will negate the gains of ordering.
Basically, is OP ready to overhaul the operations or is just willing to do something nice just for now?
Ideally, a book cover and info page should be scanned/photo'ed on first touch either by receiver or shopper and sticker coded somehow as processed, then left wherever. In case any jewel-worthy titles uncovered from OCR, the book could be located (stickerwise, date log, crate, whatever) and brought to prominence and priced as appropriate.
Unleashing imagination, as an incentive and QC strategy - some sort of automated OCR and lookup could locate the pointed book on amz or elsewhere and thus reviews and going price vs rummager's deal.
Either way, I'd see this more of a business question, rather than a technical one. Donating a technical solution is fun, but without changing the operations process is not going to be sustainable.
In a bookstore, this is a virtue. But we appear to be dealing with a book barn. Perhaps the patrons of book barn have not wandered in by accident while searching for a bookstore :)
For OP: I think you might be better off photographing the ISBN and then using a service or script to do a lookup and associate that with a cover and title. Various editions might not have their covers recorded in a database, and titles will give many dupes, but an ISBN will uniquely identify a book.
Additionally, OCR'ing stylized text is problematic. I wouldn't expect easy reading of covers, particularly of used books.