The worst is that the fees only cover the cost of running ISO the-organization: standard writers are not compensated by ISO for the work they put in.

My trick is to, for technical stuff, look for working groups and their mailing lists or other collaborative spaces, which are sometimes in the public, and get the latest working draft that they put out before it was turned into an official standard.

That's how I learned C in-depth in my high school days from the C9X (became C99 :)) draft standard.

Edit: clarify that ISO is not paying for the work being done on the standard, instead of that "writers usually do all the work for free".