Well, looks like you need to spend a lot of time researching (online and good marine beginner books) before buying anything. The first thing you should be aware of is that keeping a sw tank can become very expensive very fast if you are buying high-end equipment, nice coral colonies, fish, live rock etc. By comparison, I can set up fw tank for next to nothing, just with my spare stuff I have in storage. Typically, a nice coral will set you back $50+ unless its a small frag (cut off "baby" piece of coral). What you might consider expensive for a fw fish (i.e. $15-20) is dirt cheap for a marine fish (more likely to drop $30-50 for a tang). You'll need to get more powerful lights (LEDS are cost-effective over the long-run, but some reefers prefer T5HO or even metal halides). Really, don't buy anything till you spend the next week or two (or more) reading up on how to set up marine tanks, cost of equipment, and other issues related to this side of the addiction.