Jeremy just for clarification is the tank 10 inches high or 18? If it's the tall I would agree with TL above that some stronger lighting would be a good idea. If it's short though I suspect the light you have would get you along for awhile.
Skimmer you can skip, add it later if you see a need. The other great hangup for many people is the claimed absolute requirement for RODI water. That kept me out of salt for a long time as it is simply not possible for me to have one for logistical reasons in this house. So I stuck to a 10g, got premixed saltwater from the LFS and some jugs of cheap distilled water from the grocery for topoffs. Has worked fine. I've even topped off on a few occasions with (gasp! shock! horror!) plain tap water and somehow the heavens have not opened, nor the thunder roared nor lightning flashed, in fact there was no noticeable difference at all. Parameters stayed fine, no algae explosion or any other dreadful events. your mileage of course may vary; I have well water with no chemical treatment and fairly low TDS (total dissolved solids) and maybe that makes the difference.
But otherwise just as TL said: get salt (any brand made for marine tanks is about as good as any other), argonite sand, dead rock and live rock in a ratio of about 3 or 4 to 1 (the life will spread from the live rock to the dead stuff and this will save you a ton of money.) A HOB stuffed with plain filter floss and maybe pouches with some carbon and phosphate binder like Phosban or Rowa. A small pump (i use a Rio+50, which is very small indeed) to stir the water around. Set it up, turn everything on, and wait a few weeks and observe, testing of course on a regular basis.
after a month or so if params are good, or maybe even a little before they're completely stable if you have an early algae problem, get a couple-three turbo snails and some blueleg hermits. A few more weeks and if numbers are okay you are good to go.
of course if Greech drops in listen to him and not me, he's been doing this a lot longer than I have and we all rely heavily on his expertise. Welcome to the dark side, have a cookie.