According to my DB the lowest price is $25.99 for RAINPOINT Sprinkler Water Timer Watering System (in Banggood). You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Latest coupon code price check (UTC time):
Temperature: 38 to 120 ˚F (3 to 50 ˚C), Size: 4x 4x 1.6in (10x 10x 4cm), Max. Flow Rate: 10 Gal/Min (35L/Min), Brand: RAINPOINT, Weight: 6.6oz (187g), Working Pressure: 0.5-5.0 Bar (10-72.5 PSI), Battery: 2*AAA Alkaline Batteries (not included), Inlet/Outlet Thread: 3/4” GHT
Banggood ($25.99)
Banggood warehouse is located in China. There are no active coupons for this product, but the price is pretty low isn’t it? Well, is it a good price anyway? Cool, average is $26.85, so current price is lower!
Link: Banggood product page
Price: $25.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGGarden20, BGMX283, BGe6ad5f, BG525c06, Cuponation9, BG022423
(these codes were not working in latest coupon update, but you can check them out anyway)
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 RAINPOINT Sprinkler Water Timer Watering System.
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)).