Aliexpress
Click here… to search for Xiaomi Wowstick H1 Screwdriver Set on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (16.99 USD): 47f85a
Coupon (18.59 USD): aff7off
(CouponsFromChina.com tip: coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Old coupons (from the oldest to the newest): caae96, bgsport
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Price history (for all/most countries) for Xiaomi Wowstick H1 Screwdriver Set is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).