[Request] How much would it cost to send an Olympic pool's worth of water to the moon?

XKCD did a video about what it would be like to swim in a pool on the moon. He makes reference to getting the water to the surface, but stops short of calculating the actual cost for an Olympic pool.

How much would it actually cost to launch all of the water needed for an Olympic pool to the Moon? Assume it's ok for it to take multiple trips.