Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (34.19 USD): BG10OFFAFF
Coupon (34.19 USD): BGwhielabel
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): 1aed1e, 502C6B, BgAuMotor, TTxBG10, BGGPST6, BGGPS39, BGAki01, BG25MOTO, BGMoto67, BGmotor9, BGIMGPS12, BGMotor25, BG18SFMP, BG9485GPS, 0e7f33, BGINMO
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for iMars Micro GPS Tracker.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).