Check coupons or create price alert down below. Do you want to know what the best price is?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Working voltage 3V, Green light Suitable for moisturizing, Red light Water shortage, Weight 30g, Working current 10uA, Size 131x 25.1x 10.9mm / 5.16x 0.99x 0.43inch, Rated power 0.03W, Battery 1x 3V CR2032 button battery (not included), Color White, Product name Flowers and plants detector, Blue light Too much water, Material Shell ABS plastic + detection sheet material-glass fiber epoxy copper clad board, 05, Measurement accuracy -0
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($9.99): BGcaa3e6
2. ($13.80): BG1efeb0
3. ($13.95): Terence
4. ($13.95): 2203ActiesNL
5. ($14.10): BG00c906
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGOOR3WW, BgcLuBofErtA10, BGZKHDW1, BGTEST37, BGAFF10OFF, BGGDJUT7, BGTESCN02, BGHONEY2110, BGAP2803, BGwhielabel, 13f142, BGAU0407, BG10OFFAFF1, BANGGOODSD, 00c906, ADMITAD2212, BGAlerabat1
(probably won’t work, but you can try them out)
Price history and price alert
Here is price history (for all/most countries) for Smart Sensor Plant Flower Monitor.
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)).