Okay, to outline all of these because stuff has just been thrown at you:
Sand and root tabs - effective for your situation. Easy, cheap, and simple to acquire.
Eco complete - Extremely popular, effective, looks nice. Comes in black with 2 different available grain sizes. Harder to find and expensive. Will still need root tabs.
Flourite - same as eco complete. Looks like a sharper edged gravel and is varying shades of brown.
Aquasoil - More expensive than the previous two options. Possibly the best commercial substrate available right now. Most expensive and requires some special steps. Likely overkill for your situation. Will need root tabs.
Dirting - Organic soil with a sand cap. Very very effective and cheap. Leeches nutrients for a period of time requiring water changes. Bad choice if you have diggers. Will cloud the water when you pull up plants. More of a specialized substrate choice. Wouldn't recommend for a beginner. Will need root tabs.
