Without addressing any specific property, rent rates go up or down depending on the desirability of a home and area. If a home is in a nice area, convenient to work and play it will receive high demand and rent may go up. If a once nice neighborhood becomes a not so nice area, jobs go away and the area is poorly kept, crime rises etc., the ability to attract a renter at a high rate will go down, so rent may go down.
One related note, if you see a very low rent for a property here, on craigslist or other online sites, tread very carefully. Do not send money hoping to get keys by mail. There are a number of scams online, please don't fall for them.