Coffee Space 
I have embarked on a project to build a cheap robot. Like most of my projects, I set about with an idea of the sort of price I would like to pay and what I would like to see for my money.
The parts list is a follows:
4x 9g servos (~£4.00)4x Wooden lolly sticks (~£0.20)1x Arduino Uno (~£3.00)1x Wire (I used an old vehicle wiring loom) (~£0.80)1x 3.7V LiPo (~£2.00)As you can see, this project should be build-able in about £10. I’ll leave you to convert this amount into your respective currencies. I mostly get these parts from Banggood and AliExpress. People have recommended Alibaba, but for one time buys it seems like we’re too small fish for them to really care about bad items, etc. I’ll leave that to the buyers choice.
Some of the more aware of you may have noticed that the power supply is attached directly to the power rails of the Atmel processor, despite the fact it’s supposed to be 3.3V. If one looks at the requirements of the processor, it runs up to 5V. Single cell LiPo batteries are fundamentally limited to 4.2V, meaning they cannot harm the processor. As long as the battery runs between 3.3-5V, the processor will run correctly.
There is yet another problem though, as power is drawn from the LiPo the voltage drops. Running each of the servos at the same time under load drops the voltage, cutting across the critical voltage threshold for the micro controller. To get around this, we have to move the bot in a low power manor as to prevent this prom happening. Single servo, slow speed movements are used to prevent this from happening.
NOTE: The schematics will be added at a later date.
NOTE: Code is to come at a later date.
It is certainly possible to achieve this task and there could potentially be application is putting these little low cost devices in school with kids. Breaking them is not such a great deal and a lot of the parts may be re-used.
Version 1 of the final product. This is to test whether the Arduino could handle the power of the four servos potentially working at the same time.