If you want to sound professional (concise, precise, and accurate), then writing out a script ahead of time and the recording yourself reading your script will generally produce much better results.
For about $120 I was able to construct a teleprompter purchasing some simple hand tools and parts from a local lumber / hardware store. I scrounged up an old (about to be thrown out) 14" LCD monitor and stashed that in the bottom of the unit.
