There are many sites that will tell you many things about beddings. Some sites say never to use Cedar or Pine, I agree due to the fact that there are harmful oils that in the long run can cause serious illness to your Guinea pig. The dust from the shavings can also effect your Guinea pigs health, due to allergic reactions. My female devoloped a eye infection that I believe was due to the dust particles in her eye. There are many studies out there that totally condemn the use of Cedar and Pine, I suggest that you do your on research, and I believe you will come to the same conclusion that your pets health is more important than saving some money. However, the Kilen dried pine is safe for pets due to the fact that the oils have been removed as well as the dust.
Some people such as my good friend Louise recommend to use shredded newspapers, to Me that is a fine choice. It is good for recycling and it is a cheap type of bedding. This is also the bedding that I have decided to go with. I have read were some people use hay for there bedding, personally I would not want to walk around on my dinner before I ate it, however I see know harm in using hay. I have even read where some people use towels, etc. Thats a lot of laundry if you ask Me, whatever your choice make sure it is safe for your Guinea pigs.