$18.95 – Fast Charge Mode: 3 /000mA*1 MAX / 1 /500mA*2 MAX, Output: 4.2V±1% / 1.48V±1%, Input: 5V⎓2A / 9V⎓2A / 12V⎓1.5A, 18W (MAX), Standard Mode: 2 /000mA*1 MAX / 1 /000mA*2 MAX.
According to my DB the lowest price is $18.95 for Nitecore Ci2 Battery Charger (in Banggood). Basically copy coupon, view price history or create e-mail price alert. Let’s see what best price is ATM.
Latest coupon code price check (UTC time):
Banggood ($18.95)
Banggood warehouse is located in China. Is it cheap? Well, this price is higher than average price ($16.51) There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Price without coupon: $19.95
1. ($18.95): BGTORCH10
apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BGLED07, FIN5275, F45006, BGOutlight10, BG589b2e, 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
Check out price history chart (for all/most countries) for Nitecore Ci2 Battery Charger. The lowest price was: $10.28.
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)).