$17.70 – 5V Type C 3.7V/1.2V.
According to my DB the lowest price is $17.7 for LiitoKala Lii-M4 Battery Charger (in Banggood). Basically copy coupon, view price history or create e-mail price alert. Best price?
Latest price update (UTC time):
Banggood ($17.70)
Banggood warehouse is located in China. There are no active coupons for this product, but the price is pretty low isn’t it? I think you want to know if the price is good. Well, this price is higher than average price ($15.72)
Link: Banggood product page
Price: $17.7
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG20CHARGER, BGMBCBLE, BGAFF10OFF, BGCuponation10, 13f142, BGHONEY2110, BANGGOODSD, BGCCARG, BGcharles03, BGd57765
(these coupons are old, so probably won’t work)
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.
Price history and price alert
Here is price history (for all/most countries) for LiitoKala Lii-M4 Battery Charger. The lowest price was: $12.25.
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)).