Latest update shows that NICE-POWER R-SPS3020 DC Power Supply 0-30V 0-20A costs $146.99 (in Banggood). You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Latest coupon code price check (UTC time):
NICE-POWER R-SPS3020 Regulated DC Power Supply 0-30V 0-20A High-Power Output 600W with Smart Temperature Control Overload Protection Compact Portable Digital Calibration Technology for Reliable Performance – EU Plug
Banggood ($146.99)
Banggood warehouse is located in China. Hmmm… There is no active coupon in Banggood at this moment. Well, is it a good price anyway? Maybe there’re no more promotions for this item, because current price is higher than average (which is equal $138.64)
Link: Banggood product page
Price: $146.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGe245a9, BGSPRING8OFF, BGHONEYSP, BGESJY8, BGALL8
(probably won’t work, but you can try them out)
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 NICE-POWER R-SPS3020 DC Power Supply 0-30V 0-20A 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)).