Do single OneClick users need a subscription?

No. OneClick is free for all single users. If there's only one OneClick user in your Pipedrive organization, it's completely free, Just install from market place.  When a second user is added, you'll need to set up a subscription and each seat will be charged at the current available price.

If you get help from a OneClick partner, you don't need a subscription but the experts will provide the solution and invoicing to you directly.