...but I'm not very good. So I need tips. I uploaded a song on my profile (twice) if you really want to listen. The first time I kinda held back, because I think it sounds better. When I sing louder (like in the second one), I feel that it just, well isn't good. My question is: what am I not doing right? or is it just my voice and I have to live with it?

And taking lessons really isn't an option, as I'm 16 and my parents are already paying for guitar lessons.
youre singing an octave too low. try singing higher,
and breathe through your diaphragm, it sounds like youre just singing in your normal voice
Part of it is just your voice that you have to live with but that doesn't mean you can't improve your voice. Practice singing scales with a piano and a tuner. Learn to smoothly go from falsetto to chest voice. I've heard of another thing where you sing "over a pencil". Like you put a pencil at about mouth level and start singing and you have to try and project the sound over the pencil which means tightening up certain muscles in your body. Sing from your diaphragm instead of your throat. Finally, JUST DO IT. Singing isn't a place for shyness or for egos. Everyone feels stupid when they sing at first (and quite honestly most professionals out there can't sing at all) so just do it. You have to strengthen your muscles and your voice and the only way to do that is by singing. I'm not a singer but these are just a few things that I've learned about and read.
Quote by csn00b
I hate seeing cute girls topless and what not, it just feels wrong.
^^this. Open up your throat to your liking, and keep your mouth open a good bit. Oh, and sing from your diaphragm, from the chest. Push air, just let it flow. I sing in my own band, and the interesting thing was, I learned much of how to from the school marching band, since we sang during our show this year.
The good news is that you CAN learn to sing. If I (who has absolutely NO natural ability to sing.... I was unlistenably terrible!!) can learn to sing, then anyone can.

Now, I was bad enough that I really don't think that lessons were optional. I'm positive that, left to my own devices, I would still be flailing about in my complete and total incompetence.

One thing, though..... DO NOT PUSH the voice. Sound doesn't travel on air. It travels on waves. Consider this..... when you speak to somebody across the room, they can hear you, right? Now, if there was a candle in the middle of the room between you and that person, would the candle go out? Of course not. Pushing the voice means pushing the diaphragm inwards, which is not correct. It should be maintained outwards. Pushing the voice means that the voice does not get a chance to resonate, which means it maintains, at best, a shouting quality rather than a singing quality. It also results in a tendency for the voice to go sharp. At worst, it involves a tension in your throat that could lead to damage.

The old singing teachers used to do a trick with a candle. Place it in front of your mouth - close, but not close enough to burn. If it goes out, or even flickers a lot, you're pushing.

Check the link in my sig for some good background information. Oh, and Bel Canto isn't just for operatic singing. Good singing technique is good singing technique, regardless of style. It is the tone that defines the style. Much like it would be hard to argue that Segovia didn't have good technique. Could he use the same technique and play jazz? Sure he could. He would need a different tone, though. Could he play rock? Yeah, and he'd probably be a speed demon there too. He'd need a different tone again, though.

Could I get some more talent in the monitors, please?

I know it sounds crazy, but try to learn to inhale your voice. www.thebelcantotechnique.com

Chris is the king of relating music things to other objects in real life.