12v dc geared motor 200rpm vs nema 17 stepper motor

which motor is suitable for extruder ? good performance and cheaper. i will built a extruder of briquetting

Without knowing more about your project it is impossible to say.

Stepper motors are used for the extruders on 3D printers because they need to match the amount extruded to the amount of movement of the print-head.

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Stepper Motor Basics
Simple Stepper Code

Do you need absolute precision? - steppers make this easy, but an encoder and feedback loop can also
provide this, probably with a smaller motor and less power demand (but this is more complicated).

Speed and torque requirements? You may need to choose gearing as well.