The Wound Formulary for my area of England no longer recommend Mepilex, which are a foam dressing that I've found comfortable and effective.
When I finished a course of dressings I was given more of the non-adhesive dressing that had been used, to have under my compression hosiery. There was no gauze or padding and one wound wasn't happy after a couple of days so I've used Mepilex supplied earlier.
I believe Mepilex costs the NHS less than £3 per dressing. I don't know the cost of the cheaper alternatives, but I hope they are equally good and actually available when I next have ulcers.