Right now the best price with coupon code for Raspberry PI RP2040-Zero Microcontroller Board PICO is $8.99 (in Banggood). Just check coupons out (with price alert and history). What is best price?
The RP2040 microcontroller chip is designed by Raspberry Pi
Latest coupon code price check (UTC time):
Banggood ($8.99)
Banggood warehouse is located in China. There are no coupons for this product in Banggood. Is it cheap? Well, this price is higher than average price ($7.96)
Link: Banggood product page
Price: $8.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): Cuponation9, BG00c906, BG589b2e
(there’s a little possibility that old coupon will work)
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 Raspberry PI RP2040-Zero Microcontroller Board PICO.
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)).