There are many robot kits on eBay. They all lack a "head". So to get ahead you need to make your own. I used a "Make your own Christmas tree Ornament". They sell these 2.5 inch diameter clear plastic balls that you can use to make Christmas tree ornaments. They can also make a head for your robot. Here is a picture of a robot without a head, just a servo motor.
He looks better with the clear ball over the servo.
You can also paint it and add a circuit board with some LED's for eyes and a mouth like in this picture.
Here is another DIY robot head this time it is made out of a 3.2 inch Christmas tree bulb.