LSAC no longer permits official LSAT material in PDF form (at least not the exams, bundles, etc.). You'll have to stick with the hard copies. You can use either Amazon or eBay.
Regarding eBay, be sure they are clean copies. Or, lightly marked.
... identifying the subtleties of the form you're matching at first ... quickly translate and identify the form, this gives you an anticipated ... answer choice, then match the form in an AC asap