Prime (made by Seachem) is a good water conditioner during cycling periods, or at times when ammonia, nitrite are an issue. It is very concentrated, so the smallest bottle will last months. I don't recommend using it once the cycling is done and the tank is established, because it messes with too much chemistry, but during initial cycling it is good. After that I prefer API's Tap Water Conditioner because it does the least (dechlorinates, chloramine and heavy metals) and is so highly concentrated it lasts even longer.
A bacterial supplement like Tetra's SafeStart which I believe you are planning to get.
A good test kit. If you have strip tests now, you might consider a liquid API Master Combo; this has ammonia, nitrite, nitrate and pH. These are basic tests; nitrate and pH tested periodically (once the tank is established), ammonia and nitrite if any sign of trouble occurs.