Will you be keeping corals? If no, then you can use any sort of cheap light you want. If yes, you will need to buy a specialized light for corals.
Obviously you need a 10 gallon tank. :) Sand (not play sand, be sure to get aquarium sand composed of aragonite), live rocks, a power head for water movement, water (RODI is the best kind to use, not tap), salt mix, and other stuff like test kits, a thermometer, a hydrometer or refractometer and fish food.
You shouldn't need any type of filter -- you can easily keep a tank that size nice looking by doing regular water changes.