Update for subgoal 1

   Options:
   - datacoin has very cheap rates.  Its hashrate is low and there is no
   easy automatable interface, but it's pay-once.  It's designed for
   small-medium data.
   - bitcoinsv stn is pay-once and is designed for gigabytes of data.
   Uploading may require running a full node
   - a pay-monthly blockchain like sia or filecoin could be forked to
   change its behavior to pay-once
   - others? ethereum has storage now, haven't looked at it recently