Difference between "buy" and "purchase"

Solution 1:

Difference Between has:

Buying and Purchasing:

• are two terms that are often used interchangeably. The words essentially have the same meaning, but they do differ in context. However, in modern usage, they are considered as synonyms.

• Essentially, both the terms mean to acquire something against money. However, there is some difference between them, specifically regarding the contexts in which they may be used. Buying is considered a general term, which is most commonly used to refer to everyday goods and commodities, while, purchase is considered to be a more formal word than buy. Purchasing is often used to refer to contracts and big products, whereas buying is inferred for small products. For example: ‘I purchased a piece of land’ or ‘The government purchased a huge defense contract.’ However, ‘I bought a new phone.’

• Still, it must be noted that in daily usage, the terms are synonymous. For example: I bought a new book. I purchased a new book.

Dictionary.com defines buy as:

• to acquire the possession of, or the right to, by paying or promising to pay an equivalent, especially in money; purchase.

and purchase as:

• to acquire by the payment of money or its equivalent; buy.

Solution 2:

As verbs, synonymous. You can "buy" or "purchase" one or many items. In ordinary conversation, most people use "buy", probably because it's shorter. "purchase" seems more formal. (In business, supplies are bought often via a Purchase Order. However, a "buy order" refers to an order to purchase shares of stock on stock market. There are also "sell orders" in the stock market, but I haven't encountered them in other fields of business, either.)

..... As nouns, you can't always substitute "buy" for "purchase". For instance, if I say I bought some furniture, you could ask me "How much did that purchase cost you?" but not "how much did that buy cost you?". However, this is not enforced in business English, where you might hear reference to "a buy" (especially an "ad buy"). And if anyone tells you something was "a great buy", it means he got a great deal, that is, an excellent low price, a bargain.