Im a noob that needs some help

So I have a 2000 cav with an automatic in it. I don't know much about performance. What are some relatively inexpensive mods that I can put in that will make it faster?

for cheap, your not going to get too much quicker...

intake and exhaust is the cheapest.
some roller rockers for the poor friction prone valve train
lighten it anyway possible and anything that rotates on it
Nitrous is the next best.

...anything else, your lookin at big $$$$