Most of the "mainline" toll booths in the Orlando area now require you to exit the main roadway to pay cash. The highway lanes are for "Prepaid tolls only", meaning you need a transponder from FL Turnpike or one of the local toll authorities (out-of-state transponders don't work).
You'll usually see a sign 1 mile before the toll plaza. As you approach the plaza, you'll see another sign directing you to exit right to pay cash. Once you're off the in cash pay area, there will be a sign telling you how much to pay for autos (always a multiple of 25 cents.) There will be at least one lane marked "Receipts & Change" that has an attendant; it's generally marked with a green sign. If you have the exact change in quarters, there may a lane with a blue sign marked "Exact change only", where you toss the coins into the basket.
If you're getting on or off the highway at an exit that requires a toll, there usually is not an attended lane; the only options are "Prepaid tolls" or "Exact change". So always have at least a dollar in quarters if you plan to get off a toll road and you don't know whether the exit requires a toll. Exits to other major highways either don't require a toll or have an attended lane.