There are some good plus size (if that's what you are, I am at least!) cheapy (about ?3, not sure about postage) hold ups on amazon. Search 'romartex stockings' the range of colours is huge and I always get the XL ones (I'm a size 18-20) and they fit like a dream, no ladders yet either. I have them in red, white and light blue and I love them. Might buy some more now!
I like M&S ladder resist too (constantly laddering hosiery...) if I'm feeling rich.