A few quick questions
 

Hey, I'm new here but I had a few questions. My dad just bought a 93 LX 5.0 (collectors edition, special edition, anniversary edition, one of those 3 cant remember the correct edition) so hes going to give me his 91 LX 5.0 Its completly stock and I want to get more power in it, so I'm going to get a K & N and 3.73 gears. What are some good ways to get power for a reasonable price

N2O

do a search there are so many little things that you can do like remove the silencer bump timing remove weight , remove more weight , explorer intake N2O you getting the picture.

K&N air filter, sinthetic oil, used heads

Thats a tough question, and it depends alot on what your definition of reasonable price is. Probably nothing gives you a quicker feel of extra power than lower gears like the change to 3:73's. Beyond that most everything works together, so you won't feel massive differences buying one part at a time. The big bottleneck with the 5.0 is breathing. So you need better flowing heads. But that won't help that much unless you have a little fatter cam to take atvantage of the better breathing heads, and those two items can't work to their optimum unless you have a better flowing intake to take atvantage of the better breathing heads and cam. Do you see where this path is leading? Horsepower comes a bit at a time with each piece you add, and until you have the good breathing from intake to exhaust and a fuel system that can keep up with it , then whatever part didn't get upgraded causes a bottleneck that won't let the other parts perform like they should.
If thats not complicated enough, it gets even more complicated. You have to know what your gonna use the car for. The stock parts are engineered for mostly low RPM operation. So if your gonna stop light race (green light to 100 yards or so), then other than some timing and maybe fuel changes, you'd be better off staying close to stock on your intake, cam and heads. If you're gonna make it a mostly strip car whose RPM is gonna be in the 4500 to 6500 range launch to finish line then the stock and really mild parts won't work worth a spit. Thats where you need the high compression, big ports and valves, long duration high lift easy breathing stuff, which by the way won't work in the low RPM stop light racing worth a spit. Absolutely everything in hot rodding is a compromise, So the first thing you have to do is think and plan ... what are you gonna use the car for? Is it gonna be a daily driver? Is it gonna be street/strip where a little rough idling and poor gas milage can be tolerated? Is it gonna be mostly strip where you don't care about the idle quality or milage?
I don't know how this turned into a book on my opinions about hot rodding .. bored i guess ? but in my humble opinion, the answer to your original question would be, save up and buy a good set of heads, then as you get the money, match your cam, intake and exhaust to the heads, depending on how you are gonna use the car. Give it some thought then draw up a plan rather than just buying bits and pieces at random, you'll be much happier with the results in the end!