Most international students get a student flat through several website or the ads posted on University's wall . The appartments vary in size, price and location. In the city center are more expensive than area station. Getting an unfurnished flat is cheaper, so you might consider that and then buying second hand furniture. 
All websites to find accommodation that we know:

If you didn’t get an appartment through the web site there are some alternatives. Just know that it is in general not hard get an appartment in Ancona and that 1-2 room appartments tend to be very expensive. Getting a bigger appartment together is cheaper. Check out this housing guide for hints on how to find an appartment: (only italian):