I use pool filter sand because it's inexpensive, a lot of people are fond of black diamond blasting sand (which is basically the same thing, except black). If you buy sand at a home improvement store, do not get play sand.
On the more expensive route: I've heard many good things about Caribe sea tahitian moon sand, I've just never used it because it would be so expensive.
Make sure you rinse the sand very well, it will save you a lot of headache later.
I just use API root tabs, you can also get iron supplements and other tabs, it depends on the demands of your plants. And I also dose API Leaf Zone every once in a while.