We have had our guinea pigs for 2 weeks and I have I have already totally redone their whole cage. I made the horrible mistake of believing that the people at the pet store actually knew what they were talking about and ended up with a $90- 2 foot cage and timothy hay as a bedding!
So right now our pigs are in a C&C cage (well a C cage as my coroplast is on order and will be arriving next week) Since I don't have my coroplast yet I have a garbage bag that I split to make a plastic sheet down to protect my carpet, then towels layered over that then covered with flannel. I know that there is a concern about the pigs getting at the plastic so all edges extend past the grid.
Our pigs did for a couple of days have pine shavings and they just seemed to be sneezing a lot. Now that there are not any shavings, the sneezing has stopped. So I don't really want to go back to shavings.
If flannel is acceptable I will be changing it twice a week.