Use coupon and get Solar Outdoor Waterproof Light with Sensor RGBW for $9.99 (from Banggood). You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Light Source: 2pcs LED, , Battery Capacity: 1.2V AAA 700mAh Ni-MH Battery, Function: Light Sensor, Charging Time: 6~8H, Light Color: RGB+Cold White/ RGB+Warm White, Solar Panel: 2V 120MA 0.24W Monocrystalline Silicon Laminate, Waterproof Level: IP65, Material: ABS+PC
Latest price update (UTC time):
Banggood ($9.99)
Banggood warehouse is located in China. There are no coupons available at this moment in Banggood. Is it expensive? From what I can see this price is higher than average price ($7.96).
Link: Banggood product page
Price: $9.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG589b2e, BG014927
(system checks these coupons on every price check (like once per 24 hours), 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
Here is price history (for all/most countries) for Solar Outdoor Waterproof Light with Sensor RGBW.
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)).