Looks like the gang has most of this covered, but I thought I'd chime in with my two cents.
A ten gallon is certainly pushing it for a clown, but as the only fish, it should work. That's provided you keep a close eye on water quality. I would not recommend an anemone for a few reasons. The first is that they are generally considered more advanced animals. I'd wait until you're comfortable with salt first. Second, it's very difficult to keep a ten gallon balanced properly. The fluctuations with good care shouldn't be too hard on a fish, but anemones are pretty delicate. Swings in temp, ph, or salinity can be deadly for them. Third is size. Anemones get big. The "easiest" is usually considered the green bubble tip, and it can get a foot across. Fourth has already been covered. The clown will not need it. Fifth is lighting. Even for such a small tank, I doubt anything short of T5 would suffice long term. Dual T5 would be best.
Your belief that an anemone would rule out coral is also not necessarily true. In such a small tank, it's probably iffy at best, but as a general rule most anemone owners also have corals.
Live sand is overpriced unless you can be sure it's fresh. Dry aragonite may be cheaper. Just get the cheapest of the two. Dry rock is great, but I'd strongly recommend at least one piece of live rock to seed the system and improve biodiversity. Get the one with the most life (algae, worms, snails, pods, etc) that you can.
Some corals that may work well for you are mushrooms (one word: bulletproof), leather, Kenya tree, etc. softies are generally easier. Later you can try out some LPS such as torch, Duncan, blastomussa, etc.
cycling your sand now may not do much good as the transferral to the new tank will almost certainly trigger a new cycle.
Fish food to cycle is fine, but a cocktail shrimp works great. If using live rock in sufficient amounts, you may not see much of a cycle at all. If you've got a decomposing shrimp and see only nitrates, it's a win.
I'd suggest a couple small hermits, and a couple each of cerith, nassarius, and trochus or Astraea snails. And don't freak out if you find bristle worms. They are your friend!
Sorry for the long post! Welcome to the salty side!
