@SUTO the G, I encourage you to follow 50$ robot tutorial. Few months ago I was exactly in your place knowing nothing about electronics, and I can tell you it's very rewarding to make everything by yourself. The knowledge you'll get this way would definitely help you later, when you decide you want to use arduino, just to make subsequent projects faster.
If you really want to use arduino, then why leonardo instead of UNO?
Leonardo is more recent, but it has some differences compared to uno, like "Serial re-enumeration on reset" (see http://arduino.cc/en/Guide/ArduinoLeonardo#toc3
). I remember seeing some extra pieces of code in arduino examples (specifically for leonardo) that would wait for serial port to be ready. I can imagine a case when you download some piece of code that does not take leonardo into consideration, and it would behave slightly different, but again those are just my conclusions - you'll most likely have no issues at all, I'm just curious why did you choose leonardo instead of more common UNO which is dedicated for beginners.
Arduino has it's own programming interface software called.... "arduino"
and it's really nice and easy to setup and use. On YT you can find tutorials, by Jeremy Bloom, on how to install and use it. It is really well explained and documented. Example programms are available within the arduino GUI and can be uploaded with just one click of the button.
You can also make your own arduino on a breadboard, but I think this is even more expensive (including the price of necessary programmer and rs232 board) than original arduino
In case you were interested, here is the instruction I have successfully followed:http://www.instructables.com/id/Standalone-Arduino-ATMega-chip-on-breadboard