Battery Capacity 1200mAh, Material ABS Electroplated, Capacity 500ml, Input 5V 1A, Color White, Waterproof IPX4, Size 160*160*68mm, Weight 300g.
Just check coupons out (with price alert and history). Let’s see what best price is ATM.
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. I am tired of searching coupons, but I found one for you…
Link: Banggood product page
1. ($25.49): BGAlerabat1
paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Price history and price alert
Check out price history chart (for all/most countries) for 500mL Wall-mounted Automatic Soap Dispenser 1200mAh. The lowest price was: $25.49.
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)).