Thanks for the replies so far. I've never purchased a new car before and never planned on it (always believed used was better) considering money is tight for me. But considering I'm basically getting the same price for my truck that I paid for it 6 years ago (

) this Cash for Clunkers program may be too good to pass up! So it's either buy a new car now or not at all (my truck is worth $1300 trade). I'm definately leaning towards the Yaris right now which is why I came to this forum first.
I guess my main issue is how do I get the price as low as possible? I'm going to go to all the Toyota and Nissan dealers in the area and whoever offers me the best deal wins. Do I go into each dealer telling them that in hopes of them not wanting me to leave and offering me a great deal? Like I said, I've only owned one car in my life and I bought it used for $5k lol. I'm very new to the world of new cars, rebates, negotiating, financing, etc. Once again, thanks for all the help!
p.s. Also I understand the 5 door only comes in auto but I actually prefer auto since I have a rough commute.