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Need help on motors and motor driver

Please help me out- I want to make a basic robot like the start here bot but with an arduino micro processor instead of picaxe. Getting enough money to make it is a problem as I've got only $50. So I can't buy a motor shield for the arduino that I will try to assemble myself an a breadboard. I have been through a tutorial that teaches you to make a motor shield using a L293D motor driver but the problem with that is that the stall voltage of motors you can use with it is very low (1.2 V) while most motors that I know of have a stall voltage of greater than 3 V and I'll be using those motors. My question is- if I provide the motors with external voltage of 2.4 volts using rechargeable batteries, which is under the stall voltage and use the motor driver to provide the extra voltage then will the motors work as they do? Will continuous exposure to current under the stall value destroy the motors out will they be fine? Is their going to be any change in the programing part? While answering, please keep in mind that I'm an absolute beginner and using the L293D is my only hope of using a motor driver and staying in the budget.

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http://www.ebay.com/sch/colorfulplace888/m.html?hash=item4ab3e12226&item=320845455910&pt=LH_DefaultDomain_0&_trksid=p4340.l2562 has stepper motor for $3.90 with free shipping and another for $4.99 with free shipping.

http://www.ebay.com/itm/Smart-Car-Robot-Plastic-DC-3V-Drive-Gear-Motor-for-Tire-Wheel-/290640983055?pt=BI_Robotics&hash=item43ab8d740f has the gearmotor for $4.36 with free shipping. This motor is slow. (about 250:1 ratio) Output only turns 20 rpm at no load and ~14 revolutions per minute under load.

This one may not be in China, but http://www.robotshop.com/solarbotics-gm9-gear-motor-9.html?utm_source=google&utm_medium=base&utm_campaign=jos  has the Gearmotor 9 for $5.46 each.

The SN754410 has the same quad half H-bridge design as the L293D. It does all the same things but with a much longer name :) Same pins, same size, same connections.

The instructable you linked to is the basic schematic to use. You will have forward and reverse capabilities with either chip. There are other ways to set it up but that one is the easiest.

For motors you probably want something like:


or maybe these

This is also suitable (edit: just noticed it has a weird backshaft to it. Maybe not as cool as I thought at first).

This list is nice because it lists what each motor's stall current is right in the description. Be sure not to exceed the 1.2A or 2A, depending on the chip you go with.

I think you have it confused. The 1.2 number comes from the chip's amp rating. It's stall current, not voltage. It can handle voltages up to 36V. You need to look at your motor's stall current and make sure it's under 1.2A if you're going to use the L298D. The stall current is the electricity it uses when the motor is on but held stationary; the worst case situtation. If it pulls more current than the L293D can handle it will burn the chip up. Any current under the chips rated maximum is ok, no damage will be done.

You should also look at the SN754410. Very similar to the L293D but can handle more current (bigger motors) at a similar price.