Template
Although nano in itself is very cheap (all that is needed is a single replicator and raw materials), good templates (or instructions) for the assembler may be less accessible. While there is an a huge selection available on public domain, some of the best templates may be at the bottom of a 6000 year old archive at the Fomalhaut ISObanks, or only available in the Alexandria or Aleph Absolute Computronium nodes.
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