<em>Al tomar un taxi, </em><em>te aconsejo</em><em> que preguntes por los precios</em>
In this sentence, the indirect object pronoun for the second person singular (te) is being used. An Indirect Object Pronoun is a person that receives the action of a verb indirectly. Its purpose is to tell you <em>to whom or for whom</em> something is done. Here the action is being performed <em>for you, </em>so aconsejo is the conjugation of the verb aconsejar for the first person singular matching this indirect object pronoun.