like melosu said go with lr
. Only get live sand if its not that in the bag stuff, it's almost wothless and expensive compared to most other sands.
Also crushed coral is not advised either.
Honestly I would wait, research a lot more, asks a lot more questions, and figure out EXACTLY what equipment you basicly need and what types.
For filtration you could get off with a simple HOB
power filter, or if you have a little extra money og for a canister like afluval.
I would recommend putting damsels with clownfish. They don't really like eachother from my experience and will pick on most other things contrary to what a lot of people say, ha yeah totally non- agressive to inverts my butt.... In smaller tanks theres the agression issue so it'll be worse than in a bigger tank.