Ok, i am VERY new to the robotics "world" and i was wondering if anyone had a good design that doesn't cost very much, because i am a kid and dont have a job so a fair sum of money isn't really in my grasp.
GWS modifed servo - get 2 - $10.75 each = $21.50 - http://www.solarbotics.com/products/22140/
Freeduino - get 1 - $26 - http://www.solarbotics.com/products/28920/
4 AA battery holder - get 1 - $2.75 - http://www.solarbotics.com/products/bholdaa_4_cell/
Whisker sensor switch - get 1 (pair) - $5 (or make your own) - http://www.solarbotics.com/products/tact3/
All togther about $55. A GP2D12 IR could be about $12 later on, if you wanted a distance sensor instead of a bumper sensor. Sonars run about $25 each.
Add some AA batterys, some wire and some wood paint stir sticks to clamp/glue it all on, and you have a robot. THe reason I chose one store was to limit the shipping costs, all stuff from one spot. Solarbotics doesn't have much for sensors though. Might be able to come up with simliar parts at Sparkfun, or Robotshop, or Hobby Engineering.
You're such a softie robologist, doing all the homework for him =D
I'd just like to add that the Freeduino board there is easy to reprogram and won't be permanently fixed to your first bot (unless you glue it on or something) so although it's the most expensive part you'll get a lot of use out of it. Come to think of it, the whole Start Here bot is pretty easy to disassemble if you don't use anything too permanent to build it (double-sided foam tape is, as the tutorial suggests, fantastic stuff for smaller bots).
Take a look at the Start Here bot and see how much it will cost you to source the parts. Don't forget to take into account any tools you may have to buy that you don't already have or can't borrow.If the total cost is too high regardless of where you source the parts (how much of your cash do you actually want to spend, if it is less than $65?), then you can make some cost-saving alterations to the start here bot, but it's already pretty simple for a real programmable bot.