ok ive been doin a little research and i think drill motors would be the best idea for me as they include gearboxes and ill get chargers/batteries for them. So can someone show me where i can get good priced drills ?

Also im having a little trouble working out exactly how robots are controlled, usually i would just buy all the bits and have a fiddle but im really want to know what im doing before i buy stuff as i dont have a huge budget and i dont want to break anything so could someone please give me a for dummies explanation of how my receiver interacts with my speed controller, how my speed controller then interacts with my motor and where along the line and how do i acheive tank style steering, oh and why do i get servos with my transmitter and receiver, what do i do with them.

Please forgive my ignorance - im sure you guys had to ask aswell sometime !