Allegedly don plans to charge all our allies for the cost of having American troops there plus 50%. Is that extortion or good business?

That is the exact formula for the allies becoming UNALLIED.

What do we have that they need this badly?  

I'm not sure what power he holds over them.  
   
If they cannot unite and SHUT HIM OUT? If they cannot unite and not do business with us?  If they cannot unite and tell the USA to go stuff it? 

Then Trump is right.  These allies are worthless.    They have to prove their worth by cutting off their relationships with the USA while Trump is in office.  

Can they?  That would be swell.  The ALLIED NATIONS THREATEN THE USA WITH CUTTING US OUT OF THE AGREEMENTS BY FORCING TRUMP'S RESIGNATION.  WOW WOW WOW.  THAT WOULD BE RAD

If they do not want to pay....we bring our soldiers home.  
Some allies have spoken up and said come to our country we will gladly pay.

For normal people that would be bad business (stupidity).  However, for Trump it's business as usual.

Thanks to our "mind everyone else's business' policy, the US isn't the most liked country in the world anymore.  Our motto seems to be, 'bomb first and invade later'. While to those being oppressed, this may seem like a "godsend", they quickly learn that it's not.  Sure, the US may take down an evil dictator or 2, but they leave behind utter chaos.   We can bomb, but we can't fix the mess we make.  Not the best way to make "friends".  To make matters words, the egotistical game show host who's (supposed to be) running the US has managed to tick off just about every government in the world.  It's come to the point where many nations (even once close allies) see the US not as a friend, but as a bully.  And no one likes a bully!

If my googling is accurate, the US has 95% of all the foreign military bases in the world - 800 (more or less).  France, Russia and Britain have a total of 30 - combined.  Rather lopsided figgures.  If countries don't pay the US for housing its soldiers  and their base on their (the foreign country's) territory, what happens?"  Does the US simply pack up and go home (you're on your own!)?  Does it force the country to pay? (If ya don't pay, we still stay but we ain't protecting ya if somethin' were to.. say... "happen".)

50% sounds ridicules - no country is going to pay that. Trump will get nothing but poor relations with most of the Countries in the World. There are radar stations in Canada's artic they were put there as early warning in case Russia try's to attack the US by going over the North pole maybe Canada should tell Trump they want a 50% increase in maintenance cost.  Cheers!

We provide aid to countries in the form of military presence to support our national interests as well as those of the country we are occupying. It is, and should be recognized as, a privilege to be allowed onto their soil to defend our allies against threats to our combined common interests. 

Sadly, the laziest, stupidest, most inept, compulsively dishonest and unfit moron to ever occupy an ill-fitting suit in the WH, he of the multiple deferments for mythical heel spurs, has no concept whatsoever of international cooperation, of the value of hard-won longstanding treaties, of the need to lead from the front, or of honor, duty or morality has chosen a mafiosi ideal of running a protection racket instead. 
Let’s make a few bucks, even if costs us our integrity and our soul. The Trump Creed. 

Even sadder still are the ranks of dim bulb partisan lemmings who cheer on the whims of the demagogue and abdicate reason and spine to serve him. This post was edited by Don Barzini at March 12, 2019 3:00 AM MDT