I have a agreement with the guy selling the car that he will wait a few days before putting an ad in the paper while I see if I can get the money together to buy it.

Bilateral

Explanation:

Bilateral agreement  is a type of  agreement in which parties involved shared common understanding and each of them commit  to take an action in response of action taken by other parties which are on pre-decided basis.

since in the problem mentioned above there is commitment from one person to wait before putting up and ad and other party agrees to arrange money during the wait period it is a case of bilateral agreement

you should go do that

explanation:

is this the question?