What's the difference between "buy up" "buy down" "buy" and "purchase"

What's the different between:

• Buy up

• buy down

• purchase

• buy

When they're all supposed to mean "to pay money"?

Solution 1:

They don't all mean "to pay money" - in fact none of them mean just that.

"Buy" means "to pay money and obtain something" i.e. you pay money in exchange for the product or service. This is the verb form. In noun form it means the item that was bought.

"Purchase" is a synonym for buy and means the same when used as a verb and noun.

"Buy up" means to buy everything available in the store.

She bought up all the shoes that were on sale.

"Buydown" is a financial term used to mean paying off some part of a loan and reducing interest rates.

A mortgage-financing technique with which the buyer attempts to obtain a lower interest rate for at least the first few years of the mortgage, but possibly its entire life.