Latest update shows that 50pcs LED RGB Common Cathode 4-Pin F5 5MM Diode costs $5.99 (in Banggood). You can create price alert here, copy coupons and view price history. Do you want to know what the best price is?
Light Color: RED / BLUE / GREEN, Perfect use for home / office and industry electrical equipment and electrical appliances, Voltage: 3V, Total Quantity: 50pcs, Convenient for DIY and repair equipment and electrical appliances, Current: 20mA, Size: 5mm
Latest coupon code price check (UTC time):
Banggood ($5.99)
Banggood warehouse is located in China. I have no active coupons for you right now. The question is – is it a good price? This price is higher than average price ($3.74) for this item.
Link: Banggood product page
Price: $5.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG3901f1, BGd0b05d, 00c906, BG00c906, ADMITAD2212, 2022ACTIESNL, Terence, Tabby20, 2203ActiesNL, BG1efeb0, 8Couponsde, MVC8SPRING, BGJUNEGSG9, Cuponation9, BG589b2e
(I don’t think these’re gonna work, but you can try ’em 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
Price history (for all/most countries) for 50pcs LED RGB Common Cathode 4-Pin F5 5MM Diode 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)).