You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Total length: 465mm, Max. water pressure: 8kg / square centimeter, Jet spray tip hole: 3mm
Banggood
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): Hardware, TTxBG10, aff7off, bgssaff9, AFfbG10, BGhardware, BGBFAFF2019, BGCITYADS2019, 13f142, BG2020NS, BGMPB2020, bGhOnEy10, BGAFF10OFF, BGSS10%SW, BGdragonBoat, bgshOOp10, BGHWDEALS, BgoFErTaSchInA10, BgcLuBofErtA10, BGCuponation10, BGHONEY2110, BANGGOODSD, 00c906, BG00c906, ADMITAD2212, 2022ACTIESNL
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Do you need price history chart (for all/most countries) for Car Wash Water Spray Nozzle Gun? There we go.
Price records source(s): Gearbest, 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)).