My company is currently working with an external consultant to get ISO 9001:2015 certification. The consultant has been working with us for about 5 months. A couple of us employees have "unofficial" copies of the standard, which were given to us by the consultant. I would say we are well-acquainted with the standard and how it applies to us. Anyway, the consultant asked me to buy the ISO standard and to add it to our master list of externally-provided documents. I, however, don't think buying it is necessary. Where in the standard does it say that the organization has to buy it? As long as you follow the standard, I don't see why buying it should be necessary. I guess the obvious objection is "How can you know that you're following the standard if you don't have it?" But my answer to that would be "We hired an external consultant who told us how to apply the standard to our organization, hence we did not have to purchase the standard."