Pig in a poke

Pig in a poke is an English idiom which means a kind of deceptive trick. It is a blind bargain.
The phrase is about something which is offered for sale in a manner which hides its true value. The idiom means a purchase which turns out not to be what the seller claimed it was.
History.
The term was first used in the Middle Ages. At this time, it was common to sell meat or small animals in cloth bags or sacks called a "poke".
Sometimes people simply bought the "poke" without looking inside; and sometimes people who thought they were buying pork or a small pig were surprised to find they had been sold something else.
The idiom "pig in a poke" is about what happens when someone does not look to see what is being bought or sold.
Meaning.
The idiom "pig in a poke" is used to describe something which is purchased without the buyer being aware of its true nature or value.
The phrase can also be applied to accepting an idea or plan without a full understanding of it. In other words, it is about starting a course of action without knowing the relevant facts.
Many other European languages have a version of this phrase, but many are translated as a warning not to buy a cat in a bag. -