$50 for the Speed of Light

Well, you could use a radar to send light impulses that hit the target and then return to the point of origin, and then the time taken divided by two, along with the known distance can easily give you the speed of light. Radars aren't really that cheap though as far as I know. And measuring large distances with triangulation gets kind of messy without some half-decent options and measurement tools. I'd be impressed by a solution which doesn't have any known values as a base, such as the distance to the moon or Sol from Earth.

And iceman, this is an experimental question.