16.99 USD – that is current price with coupon for X13 Hidden Camera Detector (in Banggood). You can create price alert here, copy coupons and view price history. Best price?
Latest coupon code price check (UTC time):
Banggood (16.99 USD)
Banggood warehouse is located in China. I can’t find any active coupons for this product in Banggood. Is it a reasonable price for this item? IMHO this is a good price, coz it’s lower than average (17.03 USD)
Link: Banggood product page
Price: 16.99 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGTOOS729
(these coupons are old, so probably won’t work)
Aliexpress
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for X13 Hidden Camera Detector.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).