Yikes, I'm not paying $28 for no saddle cover.

My $12 Brooks cover (which I got for $8) works just fine for me.
If it's raining really hard I'm not usually out on my bike anyway. In case of some freak downpour I have an extra grocery plastic bag tucked in my saddlebag for double protection. Never had to use it yet. Both of them roll up into tiny balls that weigh nothing.