Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. I found coupon for you. Check this out.
Link: Banggood product page
Coupon (10.73 USD): BANGGOODSD
(CouponsFromChina.com tip: you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): vipupgrade8, TTxBG10, aff7off, bgssaff9, AFfbG10, BGKT3566, BG5131, BGBFAFF2019, BGCITYADS2019, BGVDay10%off, BGskuG5, BGHOMEG12, BGAFF10OFF, bGhOnEy10, BGdragonBoat, BGSS10%SW, BGHome15%, BgcLuBofErtA10, BG10OFFAFF, BGwhielabel, 13f142, BG10OFFAFF1
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for Skull Design Transparent Glass Cup is here.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).