Many Rabbonim hold if you're in kollel you need not give Maaser.
Ok. There are Rabbonim that hold that you only have to give massir after personal expenses. Since massir is on profit and profit is after expenses.
OP said they are not getting supported.
Masser is a Minhag
The one above takes care of everyone.
How do the first comments jive with the last?
I don't want to get involved in the whole maaser is a minhag, maaser is a chiyuv, maaser ksafim is derobanan, deoraisa, etc.
Hashem provides for all of our needs, one of which is a parnassah. He gives us money: some for us, some for others. The way we handle the money which is entrusted to us for the benefit of others is a barometer by which Hashem decides (or not) to entrust further monies to our care.
Should a person, chas v'shalom, mismanage that money the Wealthy Benefactor may find another money manager.
In my very humble opinion, saying "well, I make $x.00 a week/month, and my expenses, are $x.00 a week, too, so I am absolved from maaser," even if there is a yesh lismoch, is foolish.
How many of us truly have no room in our budget for maaser? How many could cut a starbucks coffee from the daily ritual, or not have two side-dishes with dinner, or maybe just drink water for a week instead of soda? Sure there may be some, but I imagine they're in the very small minority, thank Gd, and it is those the rest of are tasked to assist with maaser, not run away from.