One of the challenges facing novice readers, and certainly children with dyslexia who typically read very slow, is to keep track of where they are in the text.
These reading rulers may prove to be helpful, and they are very inexpensive. Alternatively, you could visit your local office supply store and look for a blue or soft grey transparent. Don't go with rulers which are not transparent, as they rob the child of the context. Rulers that are made of non-transparent plastic only display the single line of text, which robs the child of the ability to predict inflexion.