$14.66 – Output Voltage: 4.35V ± 1% / 4.2V ± 1% / 3.7V ± 1% / 1.48V ± 1%, Input: DC 5V/2A 9V/2A 18W (MAX), 000mA*2 (MAX), QC Mode: 1, Output Current, Standard Mode: 1, 500mA*2 (MAX).
I have checked all old coupons and price is $14.66 for Nitecore UM2 Battery Charger (in Banggood). You can create price alert here, copy coupons and view price history. Best price?
Latest coupon code price check (UTC time):
Banggood ($14.66)
Banggood warehouse is located in China. Coupons for Nitecore UM2 Battery Charger? Nope, there’re no coupons in Banggood. Is it a reasonable price for this item? It’s a good price, isn’t it? The average is $14.84.
Link: Banggood product page
Price: $14.66
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): BG2434P, BGUM2, BGTBFL, BG13TH, BGF1111, fInbG2020, BGff2020, BGUM213, BGAFF10OFF, BGTT10, BGSM30%, bGhOnEy10, bgshOOp10, BGUM24, BG14TH26, BGTBD, BgcLuBofErtA10, BGCZ1111, BG1128, BGBFC06, BGCuponation10, BGNTUM42, BGNTUM, BG10OFFAFF1, BGUM4, BRANDNC, 502C6B, e2bcea, linepayflt, BGUM4A, BGNTUM4, BG1106YR, BGCZ1107, BG1106YB, BGBFC04, BGYW13, 13f142, BG10OFFAFF, BGwhielabel, BG330e37, 4BLF, BGJH37, BANGGOODSD, 6GSGIT, BGTorch4, BGYW82, BGdeals307, BGZUZU088, 00c906, BGYW91, BGJH56, BGtorch2, BGsmart088, BGtorch3, BGALIBUY085, BG6ff6f4, BGAlerabat15, BGtorch7, BGJH64, BG675bad, BGALIBUY088, BGAlerabatI, BGOutlight10, BG589b2e, BGd57765, BGTORCH10
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Aliexpress
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Price history and price alert
Here is price history (for all/most countries) for Nitecore UM2 Battery Charger. The lowest price was: $13.92.
Price records source(s): Gearbest, 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)).