4-stroke outboard winterization on a fishing boat (should you choose to) is 2.2 hours at whatever the shops labor rate is, plus the cost of materials.
It entails changing the engine oil/filter, changing the lower unit gear lube, adding stabilizer to the fuel, draining the vapor separator if so equipped, or draining the carbs if not. Disconnecting the fuel supply hose, charging up the battery and then disconnecting the ground lead. Then you add a splash of RV antifreeze to the livewell drains, and blow the water out of the speedometer tubing. Charge up the trolling motor batteries and disconnect the ground lead(s) on them. Put a squirt of grease in each trailer wheel bearing to push out any water, then cover the boat up and kiss it goodnight. 😘
Expect to pay 280.00 - 320.00 P&L