Robot Kit?

i want to buy a robotics kit like the Vex Robotics Design System but more cheaper…anybody know any website?.

Vex doesn't really have any competition in robot kits that are so large. but all the parts are fairly common versions stuff you can buy individually.
Smaller kits include the Lego minsdstorm, Fischer Tecnik's series, Parallax Boe bot, etc. The cheapest I know of is INEX Global's Robo-box series.
I carry some in my store