A mortgage in the 5 towns might cost you $3000-$4000 a month (Property taxes alone are over $1000 a month)
The reality is just 6 month of raising a mortgage for this would be $24,000.
Its very hard to raise that kind of money and not a very good use of limited Tzedakah money.
And Brooklyn might be a similar amount although the Property taxes would be lower. Houses on Bedford Ave easily are worth over $1 million dollars