Re: How about a Lunar Cycler?
You would need to be doing regular runs there and back before it was worth while.
Also, with such frequent orbits, the "lumpy" gravity field of the Moon would soon start to mess the orbits up (assuming a stable orbit exists anyway) so you'd need a good propellant budget for course corrections, and constant flight monitoring, which all add to the cost.
And yes, the idea is taken from Aldrin's Mars cycler.