Holographic Genie in a Bottle, Innovative optical illusion in marketing

Use a xenon strobe light blasts your shadow onto a light-reactive vinyl screen for a few moments.  Walk away from your shadow.  Shadow optical illusion. Price: Less than $20

Desktop barometer and thermometer that uses the principles of buoyancy and air pressure. The thermomether (left) uses the principle invented by Gallileo in which the appropriate floating weight tells the temperature. The barometer (right) is a world mapamundi with fine etched continents.  Price: Less than $25

Place this prism in the disk shape on a window, and when light strikes it, the inside of your home will be filled with rainbows created by the prism.Price: Less than $16