Found these Adidas socks for $8 at Kogan, available with the free shipping coupon.
Adidas Unisex Crew 3 Pack Socks (White/Black)
https://www.kogan.com/au/buy/adidas-unisex-crew-3-pack-socks…
Adidas Unisex No Show 3 Pack Socks
https://www.kogan.com/au/buy/adidas-unisex-no-show-3-pack-so…
Adidas Unisex 3 pack Trefoil Liner Socks
https://www.kogan.com/au/buy/adidas-unisex-3-pack-trefoil-li…
Adidas Unisex Trefoil Liner Socks (White/Black/Medium Grey Heather) (only 27-30 US left)
https://www.kogan.com/au/buy/adidas-unisex-trefoil-liner-soc…
Adidas Unisex Ankle 3 Pack Socks (White/Black) (only 39-42 EUR left)
https://www.kogan.com/au/buy/adidas-unisex-ankle-3-pack-sock…
Also available but $10.99:
Adidas Unisex No Show 3 Pack Socks (Black/White)
https://www.kogan.com/au/buy/adidas-unisex-no-show-3-pack-so…
Did a check of the Adidas website and https://www.adidas.com.au/trefoil-liner-socks-3-pairs/FT8524… goes for $20 RRP vs. $8 at Kogan