According to my DB the lowest price is 20.78 USD for Nitecore UM2 Battery Charger (in Banggood). Basically copy coupon, view price history or create e-mail price alert. What is the best price?
Latest coupon code price check (UTC time):
Banggood (20.78 USD)
Banggood warehouse is located in China. I have no active coupons for you right now. Is it a reasonable price for this item? Well, this price is higher than average price (14.84 USD)
Link: Banggood product page
Price: 20.78 USD
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
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
(you can check these old coupons out, but these probably won’t work)
Aliexpress
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for Nitecore UM2 Battery Charger.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).