市场价

• 亠(lid; cover)ASSOCIATIVE
• 巾(cloth; towel)RADICAL

A market is a place where goods are displayed below and covered by a roof above.

• 土(earth; soil; land)RADICAL
• 勿(don't; must not)PHONETIC

A wide field of land sounds similar to the word for things or objects.

• 亻(person; human)RADICAL
• 介(middle; center; intermediate)PHONO-SEMANTIC

Price is determined by a middleman standing between two trading parties to mediate the deal.