What's the reasonable price or at what price would you consider buying a lucid dream mask or lucid dream induction device, such as the NovaDreamer or RemDreamer, including features like:

LCD display for setting various parameters;
Both sound and visual cues;
REM sleep detection;
Two way communication.


Just for reference, The Rem Dreamer, which is the only lucid dream mask I can find available online at the moment: Shop REM-Dreamer*, is sold at 147 Euros, which is 190 US dollars.