For those who prefer individual memberships.
"Share the fun of Nintendo Switch Online! Buy or actively extend a Nintendo Switch Online or Nintendo Switch Online + Expansion Pack 12-month Individual Membership, and receive a 12-month bonus code to give to a friend. Offer ends December 1st!"
T&Cs from page
"Only purchases from Nintendo eShop, the official Nintendo website and My Nintendo Store are eligible for this bonus offer. 12-month Individual Memberships of Nintendo Switch Online and Nintendo Switch Online + Expansion Pack are eligible, whether starting a new membership or actively extending an already existing one. Excludes codes included in console bundles. Automatic renewals and download codes purchased from other retailers are not eligible. A bonus 12-month code will be delivered via email within 72 hours of purchase. The bonus code will match the plan type of the qualifying purchase and be valid until end of January, 2025. Offer valid once per customer."
According to reddit post, it works for UK&EU regions account (EU19.99). (You can change region in account settings and change it back later.) Also remember to use a card without international transaction fee.
Edit: better pricing at South Africa store https://www.ozbargain.com.au/comment/15975301/redir
Posting this deal as personally I am after the bonus 12-month code as I don't need the membership immediately.