>> Is it ISO or maybe ANSI that charges for standards documents ? I forget
>> which.
> Both.
Not all. Schematron and RELAX NG and DSDL are free as PDFs. Linux standard base, ODF, OOXML, MPEG 4 as PDFs, are costless too. Often, if the standard is a conversion of an existing spec from elsewhere that is available free, such as from OASIS or ECMA, you would expect it to be free at ISO too.
See
http://standards.iso.org/ittf/PubliclyAvailableStandards/index.htmlSome committees don't bother to request the free distribution option: I don't know why PDF/X and PDF/A are not on the list for example. Few of the ISO standards are small enough to be implemented by enthusiastic, poor, casual amateurs, and charging prices re-enforces that. However, the days when only rich corporate, (com, gov, mil, ac) types could implement computer programs, are long gone.
For people's interest: recent withdrawn standards include an explanatory part of ISO PDF/X and a registration procedure relating to security.