This is the LEAST expensive I have seen this "starry sky ceiling" pinterest idea: it is a DIY Fibre Optic light installation kit available for $99. I do not believe you get actual constellations, but the kit comews with everything including the tools you need to install it. I wish I was a homeowner!
Star Ceiling, Install fiber optic star ceiling kits, tiles and domes into your living areas and children’s bedrooms. Enjoy many movies and quiet times under the stars., 20 Cool Basement Ceiling Ideas, http://hative.com/cool-basement-ceiling-ideas/,