These are economical and effective under the saddle for both wither relief and non-slip pad. We use them daily.
I've used one of these underneath my saddle pad for quite a few years now. It stops everything sliding back on my very round boy. Super easy to clean and held up really well - just boght a new one after 4+ years because it started to tear. I've never used it under a bandage but for this, it works great!