High torque motors are practically just a regular, internally commutated brushless DC Motors mounted with extra gear mechanism on top, to either raise the torque or to decrease the RPM (Revolutions per minute). These DC motors are peaceful effective 
and can be used in several hobbyist and commercial application.
Reducing the RPM whilst maintaining high torque would require adding up more complex gear mechanism hence the expense of these High torque DC motors mainly depends upon the RPM, torque and quality of the motors.The electric motor shaft from the base motor though a transmission connects the small gear box fixed at its front portion, which in turn generates the necessary torque while keeping the RPM low, the whole gears and gear heads are doped with thick viscous grease lubricant.
These High torque Motors come on numerous RPM’s such as, 5 RPM, 10 RPM, 100 RPM, 300 RPM, 1000 RPM and so forth. The price of these geared motors is based on the RPM, usually lesser RPM costs a lot more than those of higher RPM.
Applications
High torque and low rpm DC motors are well suited for robotic and hobby applications, thought how big is the electric motor is a matter of concern because it is quiet huge in size because of additional equipment box but nonetheless it would save the trouble and cost of adding external gears to the Auto Chain assembly of robots where simply the standard DC motors wouldn’t prosper. The High Torque, Low RPM DC motors includes inbuilt gearbox mechanism providing necessary torque for your robotic app. Hence these motors will be the many favorable choice for the hobbyist robotic tasks and tutorials posted right here.