Rather than continually replacing the plastic ones which result in another waste that needs to go into recycling, buy a longer lasting fabric one, usually made of nylon.   They are a lot more mildew resistant, super easy to keep clean, AND you will not find the horrible offgassing of the plastic ones.

The fabric ones may be a little more expensive, but you should save a lot more money in the long run due to the longevity of the fabric ones.