One of the major distinctions of types of contracts is between an express contract and an implied in fact contract. An express contract is when the two parties to a contract state the particular terms of the contract. For example, James says to Kyle "I will sell you my iPad for $400."
If Kyle responds, "I'll give you $350," should James accept the counteroffer, the two have entered into an express contract. This is an express contract example because the two parties, James and Kyle, explicitly expressed the terms under which the contract would occur. This is an express contract example because the terms are stated by both parties. Of the two types of contracts, express contracts are the more commonly recognized examples.