Basically copy coupon, view price history or create e-mail price alert. Best price?
Hi-Speed USB 2.0, USB-powered, Software-controlled antenna port power (50 mA at 3.3 V), SMA female clock input and output for synchronization, Half-duplex transceiver, 1MHz to 6 GHz operating frequency, Convenient buttons for programming, Open-source hardware, Compatible with GNU Radio / SDR# / and more, Software-configurable RX and TX gain and baseband filter, SMA female antenna connector, Up to 20 million samples per second, Internal pin headers for expansion, 8-bit quadrature samples (8-bit I and 8-bit Q)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
1. ($211.35): BG00c906
this code has to be applied in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): 7bcdf9, Terence, Tabby20, 2203ActiesNL, BG1efeb0, MVC8SPRING, 8BGwbg2204
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for HackRF One 1MHz to 6GHz Radio Platform Development Board.
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)).