You can get 420W DC 12V 35A Inverter for $41.99 using coupon code (in Banggood). Price history, coupons and price alert are available on this page. Let’s see what best price is ATM.
Overload Protection: Yes (120A), Input Voltage: 12 VDC, Input Current: 35A, Output Frequency: 20-120HZ adjustable, Effective range: 1-2 meters, Color: Yellow, Output Waveform: sine wave, Security protection: 12 intelligent security protections, Pulse Width: 1%-12% adjustable, Size: 200 * 100 * 50mm, Gear: frequency conversion / high voltage / low voltage, Drive: Intelligent drive computer board, Power: 68000W, Battery: 12 V DC (any model) (not included)
Latest price update (UTC time):
Banggood ($41.99)
Banggood warehouse is located in China. I can’t find any active coupons for this product in Banggood. Low/high price? From what I can see this price is higher than average price ($16.99).
Link: Banggood product page
Price: $41.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG8OFFCOUPON, TTBLACK5, BG589b2e, BGET12, BGET10, BG8FORMULAMX
(you can check these old coupons out, but these probably won’t work)
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
Do you need price history chart (for all/most countries) for 420W DC 12V 35A Inverter? 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)).