Amazon.com has Spigen USB-C to Lightning Cable 2-Pack on sale from $28.99 when you clip the $10 off coupon on the product page. ($28.99 => $18.99)
Spigen USB-C to Lightning Cable (White) $18.99
Spigen USB-C to Lightning Cable (Black) $18.99
Note, coupons are typically limited to one per account.