Size 254mm(L)x110mm(W)x49mm(T), Type-C Input 5V-2A, Work Temperature Range -40℃~+70℃, CS Interface Input 12V-8A, DC Interface Input 12V-5A, Start Current 600A, Product Name Super Capacitor Jump Starter, Capacitor Capacity 400F, Model S320, Peak Current 1200A, Brand KROAK.
Basically copy coupon, view price history or create e-mail price alert. Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($138.54): BG845979
2. ($143.43): BGSCM11
paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
There were country-specific coupon codes published on Couponsfromchina social channels and price alerts. Coupon price may vary by country, because there’re different VAT rates, shipping cost etc. There is a chance that some latest coupons are still working:
Old coupons (from the oldest to the newest): BGda8706, BGCarEle4, BGf07bb4, BGCarEle5, BG33c34e
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Here is price history (for all/most countries) for KROAK S320 1200A 400F Capacitor Jump Starter 12V. The lowest price was: $129.99.
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)).