Yes, you can pay cash tolls. You don't even need bring quarters, although having quarters all let you use unattended lanes with cash-only baskets.
From Orlando Int'l Airport to the tourist corridor and back, there are two cash tolls in each direction. Regardless of whether you use the northern route (528 to I-4) or the southern route (417 to exit 6), there are "Change-Receipt" toll booths available.
This will avoid any rental car toll service charge. If your rental car company requires "opt in" or "opt out" at rental time (most don't), you can safely opt out.
But pay attention! The cash toll lanes can look somewhat like highway exits, so they're easy to overlook if you don't expect your exit for many miles. Even if you're paying with quarters, you need to bear right to the cash toll lanes. Driving in an electronic toll lane in a rental car usually means you've just automatically "opted in" to your rental car company's toll-by-plate service (with a service fee).
There are no tolls along I-4, so, once you're in the tourist corridor, you can visit WDW, SeaWorld, Universal, and popular shopping destinations without tolls.