Hey, I can try to help you with what you are looking for. I don't know what type of corals you are looking to do, but if you are just looking to do cheap, pretty, and hardy corals, a 130-150watt power compact fixture will be a good light fixture for your 30 gallon tank. The entire issue on the light is that you want about 4 to 5 watts of light per gallon of water. Also, you want the intensity of power compact or VHO (very high output) lighting.
Next, you will want to get a hang-on protein skimmer for the tank. This is essential to help you keep the tank clean of wastes. Though it will not do the entire job, it will definitely help.
You absolultely need 30-45lbs. of live rock, preferably closer to 45 because this will serve as your natural filtration.
As a mechanical filter to simply move the water around, I would get a cheap hang-on the back filter to remove floating particles, plus you will need a powerhead to move water around in the tank.
As for a substrate, I would go with aragonite, as this is pretty easy to keep clean.
For a salt mix, you want to go with the more expensive salt mixes, as they will help put good elements into your water, such as calcium, iron, magnesium, and strontium. I would recommend using Oceanic salt. It is only about $20 extra than the leats expensive salt.
Other than that, I think I covered just about everything you will need to know to get this thing started. A reef tank will require a little more work, but you will get a beautiful tank in the process.
Please let me know if there is anything I can help you further with or even clarify. I know this is definitely a very complicated and complex hobby to get into.