Sounds OK.
Live rock prices vary. You might want to shop around. Having said that, for a smaller tank, you want to be able to pick the nice looking pieces, so paying a little more might be worth it.
Food willl depend on what kind of fish you get. Don't get food until you know what fish you're getting. Some will eat pellet food, but not always straight away, and sometimes they never will. Frozen mysis are a good bet for almost alll fish, except herbivores.
With the hydrometer, they're not ideal. If you can't afford a refractometer ($50), have your hydrometer checked against a refractometer at the LFS, so you have an idea of how far off it is.