2 of 2 Fix spelling of "Pololu", add links

You haven't define what's the limit of your budget.

However, for cheap programmable robots you can use: the DFRobot 2WD Mobile Platform and interface it with an Arduino Uno. You can also use a Pololu 3pi Robot or even a PICAXE Microbot which is already equiped with a front bumper

Look a this for more kits: 47 Programmable Robotic Kits