And contrary to what most people will tell you, a salt water tank is not much more difficult than fresh water to set up and maintain. The secret is simple; big tank, lots of circulation and limited feedings.
I myself have a three foot tank with 30 fish, a starfish, a coral and a shrimp, and only change the water every 6 months. Of course a little studying of the subject is in order, and the internet has tons of information on the subject.
Additionally, a good source of fish is important, and here in Singapore the place to go is Reborn Aquarium, (235 Lavender Street, Tel +65 6299 0930), where the prices are right, the fish are generally fresh and healthy and the staff, though busy, will take the time to help you learn about your new roommates.