motor gears help

[aruna1]

guys can i use this cheap motors to drive a robot? how to use gears to get more power from this motor? i mean are gears for this motor or any other motor available to buy or do i simply have to buy a servo to built a robot?? if they do what should i ask in order to buy them(i mean should i ask from the shop  "do you have motor gears or gear sets for this motor"?)
or do i have to make my own set of motor.if i have to make them my self how to make them?
thanks (hope you understand my bad English)

[ArcMan]

You can buy gears for a motor like this at Stock Drive, Small Parts, Inc., hobby shops, others.  Take it from a machinist (that's me - an amateur), you will need to develop some serious skill and have the right equipment to manufacture your own gear train.  If your not inclined to spend months of learning and many dollars, I would use a continuous rotation servo for your small robot needs.  They're cheap, powerful and easy to use.

[Ro-Bot-X]

I think Tamiya Dual Gearbox uses 2 of this motors. At the price of one servo, you get 2 DC motors with 4 speeds gearboxes, perfect for a small robot. But to control the motors you need an H-bridge, so it adds a little to the price. A dual H-bridge circuit like SN754410 will work well for this.

[aruna1]

thanks