You are not required to buy a membership before you start attending practices, meetings, and events; however, members do receive discounts on event entry fees. Paid membership is a requirement for holding an SCA office, and in some kingdoms, you must have a membership to take part in combat activities and to be eligible to receive awards.
Paid Members get these Benefits:
• Discounts on event admission fees
• Membership card – check in at events quickly by presenting your card
• Voting privileges in your local group – polls on local group matters are sent to those on the membership list
• SCA Publications – digital access to all monthly kingdom newsletters and the quarterly Board Minutes, along with the option to subscribe to Tournaments Illuminated (the quarterly magazine of the Society), the Compleat Anachronist series, and to paper versions of kingdom newsletters and the Board Minutes.
Additionally, your fees help support the SCA infrastructure, including worldwide liability coverage for our chapters, and the ability to maintain consistent rules and standards throughout the Society.
You can learn more about membership and/or sign up here.
The above information is from page 17 of the article “A Newcomers Guide to the SCA“.