You can find nice reusable flip top bottles at the local brew shop or on amazon.com
Clean all of your items (dishes and bottles used in the making) in a water bleach solution or in Star San.
Ingredients: 10 cups water, 1.5 tsp. Ginger root, 3 tbsp. Sassafras root, 2 tablespoons Sarsaparilla root, 1 Star anise, 2 drops Wintergreen oil, 2 tablespoon Birch bark, 2 tablespoon Wild Cherry tree bark, 1.5 teaspoon Juniper berries, 2 Cinnamon sticks, 1tbsp Molasses blackstrap, 1- 3/4 cup unrefined cane sugar. The upfront cost for all of the stuff might be a bit shocking but you don't use much per batch and the ingredients will last quite a wile (have had mine for years as we only make it once a month or so). The bottles we have had for 7 years and they still are in great shape.
Process: Add 10 cups Water to a pot and bring to a simmer add all ingredients except the sugar and Molasses. Cover pot simmer on low for 45 minutes. Remove lid and allow to cool for a bit (to just warm). Strain out all of the added ingredients. Then I add the sugar and Molasses and no more than 2 - 4 drops of wintergreen oil stir well ( There is some controversy on this online so research it before you use it )…. then add to flip top bottles.
Fill your bottles to just at the bottom of the neck of the bottle. This will allow the yeast to have enough air to carbonate the soda. When your bottles cool to room temperature add a pinch of yeast (10 grains or so), close the bottle and shake well. Place on a shelf at room temperature out of the sun and wait three days, then try a bottle. If the carbonation is good put it in refrigerator. If not give the rest a day or two more. Make sure not to shake before opening and open over a sink have a cup ready as they really get carbonated and can overflow - that's experience talking!
Here is a Word Doc for you to download it is a Brewing form for you to keep track of your process and results when you brew a beverage! It includes the recipe for Root Beer.