LiDAR sensors are EXPENSIVE, usually ranging in tens or hundreds of thousands of dollars. Even laser rangefinders cost thousands. The most "affordable" ones I've ever seen are here:
http://www.robotshop.com/high-end-la...detectors.html
(something's wrong with hyper-linking for me...) Architectural LiDAR sensors are usually on the high end. That doesn't mean you can't "scan" something using other technology, such as photography. Software exists for making 3D scans using a Kinect (other than 123DCatch. Software for scanning larger things. I'll look around). *edit* There's also acoustic scanning, using 4 or so microphones... MIT level stuff, but really cool, nonetheless