The above part is Samurai radical, in older contexts this character represented a person of status—someone with something valuable, like a warrior with his loot or a scholar with his knowledge. Legs radical at the bottom, It signifies action or movement. The middle part lid, In this context, think of it as a stall cover or a display counter. It represents the concept of “unveiling” or "presenting something that was covered ( their loot) What are they doing? They are lifting the cover (冖) off their goods at their stall. Hence selling
I’m a bit confused, are you proposing your own Wanikani-style mnemonic?
Because if we’re talking about the actual etymology of the kanji, it’s a simplified form of 賣, where the bottom component is obviously 買 (buy). Wiktionary claims that the top 士 is a corrupted form of the original 出 (to go out).
As for the origin of 買, it’s seashells:
In China, cowries were so important that many characters relating to money or trade contain the character for cowry: 貝. Starting over three thousand years ago, cowry shells, or copies of the shells, were used as Chinese currency. The Classical Chinese character radical for “money/currency”, 貝, originated as a pictograph of a cowrie shell.
The entry in Howell’s etymological dictionary looks like this:
賣 (15) バイ；う（る・れる） Shinjitai 売 (7)
The relevant seal inscription form combines 買# (seek to profit) + 出 proceed → go out to seek profits by selling → *sell*; *make money* → *be in demand*.
I suppose the etymology makes sense, though in this case I can’t say it helped me remember the kanji !
@YukaSato1: whatever helps you remember the kanji is good! Enjoy the journey.
!