Could I reflect a commercial laser off of the reflectors left on the moon by the astronauts? Would an ordinary laser pointer reach the reflectors placed on the moon? I want to reflect a laser off of the moon. How powerful must my laser be?
 A: For sure  the lasers used by the agency are strong , and what is important, the detection of the return from the reflector difficult even for the agency:

Even under good viewing conditions, only a single reflected photon is received every few seconds. This makes the job of filtering laser-generated photons from naturally occurring photons challenging.

For sure an ordinary laser cannot work.
A: The first measurement of the distance to the moon by timing the round-trip flight of laser pulses was done using a 50 Joule ruby laser (avg power during each 500 microsecond pulse was 100 kW) in 1962. That was before they put retroreflectors on the lunar surface.
https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment#History
I'm not 100% certain, because it's hard to find pricing information about lasers in that category without speaking on the phone to a sales consultant, but I'm pretty sure that there are comparable "commercial" lasers.
Obviously, the size of the laser matters, but what also matters is the size of the telescopes that you use (one to collimate the outgoing laser beam, and one to catch the reflected light,) and also, the sensitivity of your detector.
