The link you shared is about a company that made profit from bitcoin trading. You need a platform to buy and sell bitcoin and the company was giving us a platform to do so. They might have charged a very small amount for their service. And you should be clear whether you are mentioning about the price of bitcoin to be free or its transaction cost. If you want free bitcoin then use faucet or mine them. The transaction cost for bitcoin is little and might go lower in the future.