Normally, you spend a little more on your first bottle since you are also paying for the bottle deposit. Once you have empty bottles you can exchange them for a re-filled bottle and you only pay for the water, not the bottle deposit. At a Hero supermarket, you go to the store room and ask for bottled water, exchange your empty bottle, and then bring the new bottle to the cashier for payment. The cashier will usually give you antiseptic wipes, if they don't, ask for some. At Kem Chicks supermarket in Kemang, there is a water bottle station outside in front of the store, you just exchange your empty bottle for a new one and pay right there.
Many neighborhoods also have a warung or small food stall that sells bottled water.
You will need to trade your empty bottle, or pay a deposit for the new bottle. There are a variety of dispensers you can purchase or rent from your water supplier or purchase from a department store. Some are ceramic and have only one spigot for room temperature water. Others are electric and have two spigots, one for hot water and one for cold water. Before tipping the bottle into your dispenser, clean the bottle thoroughly, using the cleansing wipe around the top of the bottle.