My first suggestion would be to buy a book entitled the "The Marine Aquarist." This is an excellent resource. That being said, the phrase you'll keep hearing the most is "water quality, water quality." Reef setups require exacting standards. Excessive temperature or Ph variations will spell doom quite quickly.
The minimum size should be at least 40 gallons. In terms of equipment, you'll need the tank and stand of course. You'll also need bio-filtration of some kind. Another piece of equipment that's vital is a protein skimmer. Now one way to go is to have a wet-dry filter, a protein skimmer, a cannister filter, and a pump to push all that water through. This will help ensure that you at least start off on the right foot. Last but not least, you'll need to have the correct lighting. Too much or too little could have disasterous effects.
In terms of money, plan on at least $1,500 for the equipment (e.g., tank, stand, skimmer, filter, pump, etc.). You can spend a lot more, but I would think it would be hard to get by for a whole lot less. For price comparisons, check your local dealer against the various internet stores. The dealer should be comparable. You might expect to pay a small premium if the dealer has excellent service.
