It is possible to creatively use the booking system for a one-day membership or punch card sale.
You’ll want to create an offering for each “product” with a single, fixed event. You can see some examples below of custom questions that are relevant to a membership sale.
Once purchased, the transactions will arrive into the event and your staff can upgrade the customer records manually to members.
This gym has a staff-only custom question for “Setup?” that can be used to indicate the membership was setup by the staff.
STEP 1 - Your website/blog post
STEP 2 - The Offering Page
STEP 3 - Creative use of Custom Questions