Xiaomi LEMO Calculator (Banggood, Aliexpress: Size 162x 208x 26.5 mm, Max. Digits 12 Numbers, Type Solar Power + Battery, Screen Material LCD, Color White, Battery type Button Battery AG10, Material ABS (the best price with coupon)).
Just check coupons out (with price alert and history). Let’s see what best price is ATM.
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.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China. Coupons for Xiaomi LEMO Calculator? Nope, there’re no coupons in Banggood.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/feV
Old coupons (from the oldest to the newest): 59c904, 502C6B, CODE1573, 3b532e, vipupgrade8, TTxBG10, BGCalculator, 2019SPEDM, bgssaff9, AFfbG10, BGKTLEMO, BGBFAFF2019, BGCITYADS2019, 13f142, BGVDay10%off, BGHOMEG12, BGAFF10OFF, bGhOnEy10, BGdragonBoat, BGSS10%SW, bgshOOp10, BGHome15%, BGHOMEA15%, BgcLuBofErtA10, BGCuponation10, BGHONEY2110, BG10OFFAFF, BGwhielabel, BG10OFFAFF1, BANGGOODSD, 6GSGIT
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Price history (for all/most countries) for Xiaomi LEMO Calculator is here. The lowest price was: $7.99.
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)).