1. Click Constituents, constituent search
  2. Select the Member record
  3. Click Add Membership in the Tasks menu
  4. Select the membership details
  5. In the Amount Field, enter $0.00
OR
  1. In the Discounts section, select a membership promotion that will discount the membership 100%
NOTE: These can be created in Tickets, Discounts and Promotions, Membership Promotions