Cost of moving a bathroom?

About $20,000 or more, because you will need building permits and experienced contractors to do the work. Maybe just getting an exhaust fan installed would help with the sound effects.

It all depends on how your house is constructed. If you have a concrete foundation you are out of luck. If your floor is wood and you have a crawlspace or unfinished basement underneath, it is easy. 

I did something similar, but I did it myself to save money. I hate watching a plumber work slowly and charge me a fortune when I can do it myself. 

You can learn all the skills on Youtube. 

$30,000.00.  + or - $5,000.00

Two things to consider:

#1  Moving  it to next to the kitchen will cause bathroom odors to seep in to the kitchen.....NOT SAVORY!

#2 You can probably put a complete 12 x 12 addition WITH a full bath on your home for about $20,000.00 to $25,000.00.  Do that instead.

If you have plenty of access to the underside of the floor where you want to put the new bathroom, then it's all easy to do yourself.  But I suspect this is your very first glance at this kind of project, or else you wouldn't be asking the question here.

There really isn't a ballpark figure to give, because it would be based on nothing at all.  We don't know what your water supply situation is like, the piping underneath, etc.

If you had a closet or large pantry to move a half-bath into or, as you said, an existing laundry room, then the cost could be almost nothing - just the water and drain piping.  You could even reuse the existing fixtures so your only expense would be plumbing, and if you're even halfway competent then making connections with those is child's play.  The laundry room already has water and drains close by so there's plenty of opportunity to make things work.  If you can't make it work with the washer and dryer in place, consider moving to an over/under laundry pair.  That frees up about nine square feet in one go.

But seriously - if there's plenty of access and a place to move the fixtures into then it's mostly just going to be plumbing and time - a few hundred bucks at the outside.  But if you're on a slab, or access is poor or some other encumbrance pops up that hadn't been considered then the cost will go right up.  And if you decide to install new fixtures that's at least a cool thousand right there.

Depends on what you consider to be "astronomical."  None of those things sound like a pipe dream to me.  Removing the existing 1/2 bath is the least expensive task since it just involves capping the plumbing.  The laundry room already has plumbing in place.  The biggest job in there will be to provide the correct soil pipe for the toilet.  Get estimates from experienced contractors.  It depends on your house's existing drainage layout.  This might be complicated or very easy but you can't know until you find out what's there already.  Moving the laundry appliances to the garage could turn out to be the most expensive change depending on what needs to be done for the drainage, but it's also a very common thing to do, so usually not extortionate.  It's worth getting estimates locally.  We can't tell you much useful on here.

It is not hugely expensive IF the right sort of drainage is already there. The closet is not much more than redecoration and capping off supplies. If the laundry has a connection to a 4inch drain it should be easy to plumb in a half bath. Ditto the garage.

Running in new drains is not cheap, but not impossible either. And this is one area where if you know what you are doing you can save a lot by doing it yourself.

Moving the bathroom and washer and Dryer. means moving pipes, which means lots money. 

You can get a reconstruction company in to give estimates.