Everybody has got to make some sacrifices, everybody’s gotta take a haircut"–President Barack Obama
OK, I get the sacrifice part, but the latter part I don’t. I admit I really don’t get it. They don’t seem to go together. Anyone? 
He’s referring to respective budget allocations being chopped down a bit.
Don’t know if you’re familiar with the usage but “haircut” has long been used to refer in finance to reducing a total dollar figure – there are “haircut formulas” for estimating the reduced value of depreciated stocks, and there was a longstanding 50% “haircut rule” that limited the amount of business entertainment expenses that U.S. taxpayers could claim as deductible (guess what it limited it to?).
Take just a little off the top and trim the sideburns, please.
some should take a haircut (his friends), others should get the guillotine (the taxpayers who will cover it all). But that’s just reading between the lines 
I’ve heard haircut used to refer to a pay cut or a reduction in grade/seniority at a job. I.e., “I heard when they brought the new guy over he had four years in but they gave him a haircut down to two.” “I started my new job today; I took a bit of a haircut but the hours make up for it.”
Note that I’ve heard it in the legal arena, like law firms, which is where Mr. O (and definitely Mrs. O) has some experience. Coupled with the tax usage, I guess it’s not all that uncommon.
Don’t think of it as a trendy styling at the salon, think of it as a prison or boot camp shearing that you submit to.
It’s a phrase I hear a lot in legal settings about everybody having to cut their share.
Except the wealthiest are actually paid to show up for their shampoo, styling, manicure, pedicure and massage