Having free versions of Touch Bible means more people can own it and benefit from it by reading the Bible more often. Knowing that the Bible is being read more often because of Touch Bible is a blessing that money cannot buy!
Most versions of Touch Bible that come at a price are charging for premium features and study content, not Bibles. Some versions of the Bible, however, do require royalty payments, and those versions will also come at a price out of necessity. (Of course, paying for these versions of Touch Bible goes supports the developer and future versions.)