I'm just a college student not willing to spend much money on backpacking gear, but I still enjoy it.

Here is the problem:

1. I like hitting the trail really light
2. I don't have the money to buy really fancy, expensive ultralight products.

A couple times I have hit the trail in fairly primitive fashion, stuffing a sleeping bag into my school backpack (about 1400 cubic inches) along with a knife, water, some food, first-aid, flashlight and a couple other basic necessities.

Needless to say, it weighed next to nothing and I could hardly even feel it on my back. No tent, no sleeping bag, no tarp, no stove or cookware or nothing.

I could use this for a night or two, and have slept in some rough conditions (a cave with a ground consisting of jagged rocks, to get out of the storm) also another example is sleeping on cliff (again on the rocks) overlooking a valley, just because it had a great view. Got about 4 or 5 hours of sleep at each of them.

Anyway, long story short, I am definitely a minimalist, but I want to sleep a little bit better at night and have a little bit better gear without really making my pack heavy or bulky.

I have a (real) Kelty 3100 cubic inch pack now.

So, looking for advice. I am more of a 3-season hiker, just so that I don't have to buy fancy winter gear.

-I definitely don't want to carry a tent, I love sleeping out. I guess this means I would need a tarp for when weather comes huh?
-The last couple times I have slept on the rocks because of the circumstances and not slept real well. I would kind of like to have a sleeping pad, but wouldn't want to carry around a super bulky one that I would have to lash on the outside of my pack or something. I could get by with just selecting better spots with softer ground/grass to sleep on, right?
-What about fancy clothing? Is it worth it to buy some of that stuff?
-Lastly, the sleeping bag I have right now is pretty bulky and heavy, but since I don't carry around much other stuff, it still fits fine, so it should be ok right? It's a Kelty Clear Creek 20.

Summary: Need advice on tarps, sleeping bags, possible sleeping pads, and fancy clothing. Want to go light, but especially cheap.

THANKS in advance for the help!!!