Quick tip, if there's an item you really like leave it in your AliEx cart for awhile and check periodically. Sometimes the system will automatically give you an exclusive discount separate from the store vendor or even other AliEx deals.
My cart always has like 50 items in it for this reason

- And to pick up coins discounts in the discount finder, though this can get wonky with a big cart.
Also, for most sales where you can't "collect" the code but have to copy it, i usually go to checkout on desktop with a large sum (it will not let you paste a code for ca. 600$ if you don't have the amount to check out) and enter every code for the current sale so that it applies automatically and i don't miss out on anything.