This is probably the cheapest bedding but it is not suitable 'cos newspapers are extremely absorbant & absorb pee too quickly. Your cavies would drench the newspapers in no time & would be moving about on wet bedding most of the time. They could catch a cold easily when the weather is cold. Besides it not good for their skin & you wouldn't want skin infection from them sitting in pee soaked newspapers. Many Americans use newspaper but its much less humid over there & moisture dries faster. In Singapore you will find wet newspaper takes ages to dry.
It may sound absurd but trust me when I say that if you want to use newspapers alone, you need to use at least 20 sheets & you'd have to replace it at least after every 3 to 4 hours. Replace it any less than that & you can be sure all the papers would be soaked. Those furballs pee a lot! So save yourself the time & trouble & don't use newspapers alone. At least put a generous amount of hay or straw on top of it. For more details about using hay or straw with newspapers, refer to the "Safe Bedding" section.
Poor moisture absorbancy.
Poor odour control.