Some dishonest shop owners write price-tags unclearly, e.g. the digit 6 is written like 0. Sometimes they hide the unit or write it very small, e.g. $10/kg, they hide the "/kg" and when you pay, they tell you it is $10/g. This is not clear price-tagging.
Or some items are without price-tags, esp. in tourist spots. They sell customers in whatever price they like, selling locals $100 but tourists $200.
Skeletos
明码标价不仅要标明商品和服务的价格，还要标明与价格有关的其他情况，如商品的品名、产地、规格、等级、计价单位或者提供服务的项目等。经营者违反规定，不标、错标、漏标或不按规定方式标价，不能称作为明码标价
要求准确、醒目、易懂、美观，一货一签，货签相符，同位陈列，不错不乱。
Or some items are without price-tags, esp. in tourist spots. They sell customers in whatever price they like, selling locals $100 but tourists $200.
Я не уверен в моём русском переводе, тогда только выразил случаи тогда, когда фраза употребляется.)