You can get 2.4G Mini RC Boat Submarine for $19.09 using coupon code (in Banggood). Just check coupons out (with price alert and history). Let’s see what best price is ATM.
2.4G Mini RC Boat Submarine Spray Light Waterproof Rechargeable Electric Remote Control Speedboat Gifts Water Toys Children – Red
Latest coupon code price check (UTC time):
Banggood ($19.09)
Banggood warehouse is located in China. I can’t find any active coupons for this product in Banggood. But wait a sec… Is it a good price? Let’s see… Average price for this item is $19.89 and current one is $19.09, so it’s a good price!
Link: Banggood product page
Price: $19.09
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
There were country-specific coupon codes published on Couponsfromchina social channels and price alerts. Coupon price may vary by country, because there’re different VAT rates, shipping cost etc. There is a chance that some latest coupons are still working:
1. (27.7.2023, $17.99): BGXIFD1116
Item: 2.4G Mini RC Boat Submarine
Countries: CzechRepublic, Hungary, Slovakia(SlovakRepublic), Slovenia
Old coupons (from the oldest to the newest): BGMatt2022, BGbd0cfe, BG589b2e, BG5RCCar, BGRCCar5
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
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
Price history (for all/most countries) for 2.4G Mini RC Boat Submarine is here.
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)).