My car has become very bouncy?

Posted: 29 Nov 2013 05:06 AM PST

I drive a 2007 Vauxhall corsa 1.2 sxi. The mileage is almost 69000. Today when driving it I have noticed the back tends to bounce a lot when going over humps whether they are big or small. The same thing happens for bumps in the road. What could the problem be and how much do you think it may cost to repair?