I have just checked coupons. The lowest price I could get is $17.99 for FNIRSI SG002 Digital 0-22mA 0-10V Voltage Signal Generator (in Banggood). Price history, coupons and price alert are available on this page. Do you want to know what the best price is?
Material: ABS, Voltage output: ±12V, Packing size: about 90*70*38mm/3.5*2.8*1.5in, Size: about 89*69*28mm/3.5*2.7*1.1in, Charging method: external power supply / DC5V micro USB, Current output: 0-24mA, Colour: black, Weight: about 95g/3.4oz
Latest price update (UTC time):
Banggood ($17.99)
Banggood warehouse is located in China. Too bad there’s no coupon right now in Banggood. But wait a sec… Is it a good price? Well, this price is higher than average price ($16.99)
Link: Banggood product page
Price: $17.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG20236Tool, BG022ff7
(there’s a little possibility that old coupon will work)
Aliexpress
There’re some similar (or not) items on Aliexpress
| Image | Product (link) | Price | Coupons |
|---|---|---|---|
 |
4-20mA 0-10V Digital Analog Voltage Signal Generator 0-20mA Current Transmitter Source Calibrator Electronic Measuring Tools | $13.49 | – |
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Check out price history chart (for all/most countries) for FNIRSI SG002 Digital 0-22mA 0-10V Voltage Signal Generator.
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)).