Wow!
How many days to replace hay?
It's very expensive I can't afford it!
What other options are there?
You can use a washable fleece bedding if you can get hold of it, but Guinea pigs need a big pile of hay every single day, it is their main food source. Any that gets peed or pooped on needs to be thrown away every single day. Hay will be wasted, it’s just how it is. Guinea pigs are not cheap animals to keep