HackRF One 1MHz to 6GHz Radio Platform Development Board (Banggood, Aliexpress: 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) (the best price with coupon)).
Basically copy coupon, view price history or create e-mail price alert. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. I found coupon for you. Check this out.
Link: Banggood product page
1. ($211.35): BG00c906
you should apply the coupon 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
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for HackRF One 1MHz to 6GHz Radio Platform Development Board. The lowest price was: $149.99.
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)).