There are several bedding types that you can use for your cavy's cage. Timothy hay can be an option for bedding it is very cheap and healthy for cavies. Recycle paper products can be another option for bedding, aspen shavings. When purchasing shavings I will recommend you to buy them directly from a pet store, other than that may contain mites. Some people use bath towels which are the healthiest method in my opinion they do not contain dust, chemicals and other compounds, but they require daily change and a lot laundering. I will recommend the bath towels as I heard that they can help with avoiding any upper respiratory problems, because they do not contain any dust. If you need more details please feel free to ask me or the mods.