1. When used as a verb, pay attention to the following usage:

It is usually an intransitive verb when it means "bargaining". Pay attention to the prepositions used. For example:

We bargained with her about the price. We bargained with her.

She bargained with the shopkeeper for a blank one. She bargained with the shopkeeper for a blanket.

It means "put forward the conditions of ..." or "demand ..." is a transitive verb, followed by that- clause. For example:

He offered that he didn't have to work on Sunday. He offered not to go to work on Sunday.

Used for bargaining is [above], which means "expectation" and "expectation". For example:

We didn't expect so many people to come for tea.

The cost is much higher than he expected. The cost greatly exceeded his expectation.

2. As a noun, pay attention to the following usage:

Whether it refers to goods or bargains, or to transactions or sales contracts, it is a countable noun. For example:

This is a real bargain. What a bargain.

I bought this painting at a low price. I bought this painting very cheaply.

He made an agreement with his wife, "You cook and I wash the dishes". He and his wife agreed that "you cook and I wash the dishes".

He soon found that he had made a bad deal. Soon he found that he was doing a bad business.

Other useful expressions. For example:

That's [that's] a deal. That's settled.

Reach an agreement, make a deal