Open Hardware scanning laser rangefinder.
It is really cheap - its components cost less than $35.
Example of Hector SLAM working with this Lidar:
This Lidar is using triangulation method for measuring distance to objects. It can be shown by this picture:
Some modeled pictures of the assembled Lidar can be found here: https://github.com/iliasam/OpenSimpleLidar/tree/master/Misc/Pictures/
Now I'm updating the documentation for this LIDAR.
Some more info: https://hackaday.io/project/20628-opensimplelidar
See also another my Lidar project: https://github.com/iliasam/OpenLIDAR