Just because she is paying U$ 1000 for rent doesn't mean she doesn't have expenses as well (although nothing has been said to the contrary). Building expenses, gas , electricity. water. abl, TV, internet/phone, insurance, (not to mention the cost of furnishing a place).
If paying for a furnished apartment all these expenses are usually included.
Building Expenses poll from 2009:
http://baexpats.org/...ur-´expensas-´/
Not to mention if the payment is going out of the country the owner is probably not paying tax in their income...