There is only one such animal:
SANE drivers. There's also a GUI interface -
Scan Again. But be aware these are not for the amateur.
If I were you I'd pay the money for VueScan. It's not that expensive and includes OCR. The only other OCR program for the Mac costs $200.00.
I find it odd that you'd be willing to buy a new scanner but not willing to pay for the software that would enable you to use the scanner you already have. The Pro version of VueScan is $80.00. A new scanner will cost that much. And, the software it comes with will probably only work with that scanner. VueScan works with hundreds of scanners. To my mind you're being illogical.