Amazon has LK Liquidskin Apple Watch Screen Protectors for both 38mm and 42mm size. Both are $4.23 after applying codes listed below.
[6 Pack] Apple Watch Screen Protector (42mm Series 3/2/1 Compatible), Full Coverage
https://www.amazon.com/dp/B07DVKG9FR
Discount Code: WEAJB96D
Price: $4.23
[6 Pack] Apple Watch Screen Protector (38mm Series 3/2/1 Compatible), Full Coverage
https://www.amazon.com/dp/B07FGG7FGV
Code: WIJ6FRNO
Price: $4.23
Shipping is free for Amazon Prime Members