Basically copy coupon, view price history or create e-mail price alert. Let’s see what best price is ATM.
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):
Item size: 140x 80x 40mm / 5.51x 3.15x 1.57in, Battery: 1x 5V / 5300mAh lithium battery (included), Welding thickness: 0.1-0.15mm, Gears: 1-6 gears, Package size: 170x 115x 90mm / 6.69x 4.53x 3.54in, Item weight: 355g / 12.52ounce, Package weight: 423g / 14.92ounce, Name: Spot Welding Machine
Banggood
Banggood warehouse is located in China. I don’t think there is an active coupon right now – at least in my database.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGe4b6b7, BGGines, BGET12
(there’s a little possibility that old coupon will work)
Price history and price alert
Do you need price history chart (for all/most countries) for 6 Gears Mini Spot Welder? There we go.
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)).