Right now the best price with coupon code for 100mm 90 Degree Carpenter Square Right Angle Ruler is $5.99 (in Banggood). You can create price alert here, copy coupons and view price history. What is the best price?
100mm 90 Degree Carpenter Square L Square Right Angle Ruler Aluminum Pocket Ruler Woodworking Measuring Tool
Latest price update (UTC time):
Banggood ($5.99)
Banggood warehouse is located in China. There is no active coupon in my database right now (for Banggood). Is it good price? IMHO this is a good price, coz it’s lower than average ($6.28)
Link: Banggood product page
Price: $5.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGWDT15
(these coupons are old, so probably won’t work)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Check out price history chart (for all/most countries) for 100mm 90 Degree Carpenter Square Right Angle Ruler.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).