וַיִּשְׁמַ֣ע אַבְרָהָם֮ אֶל־עֶפְרוֹן֒ וַיִּשְׁקֹ֤ל אַבְרָהָם֙ לְעֶפְרֹ֔ן אֶת־הַכֶּ֕סֶף אֲשֶׁ֥ר דִּבֶּ֖ר בְּאָזְנֵ֣י בְנֵי־חֵ֑ת אַרְבַּ֤ע מֵאוֹת֙ שֶׁ֣קֶל כֶּ֔סֶף עֹבֵ֖ר לַסֹּחֵֽר׃
И послушал Авраам Ефрона; и взвесил Авраам Ефрону серебро, которое он назвал на слушаниях сыновей Хета, четыреста сиклей серебра, текущие деньги у торговца.
Rashi
וישקל אברהם לעפרן AND ABRAHAM WEIGHED TO EPHRON [THE SILVER] — The name Ephron is written defectively (without the ו) to indicate that there was something missing in Ephron viz, sincerity — because he promised much but did not do even the very least (Bava Metzia 87a): He took from him big Shekels, viz., centenaria (worth a full 100 smaller units) as it is said, “money current with the merchant” which means, such coins as were everywhere accepted as worth a full Shekel — for there are places where their Shekels are of large size, centenaria; old French Centenars (cf. Ruth R. 7).
Chizkuni
וישמע אברהם אל עפרון, “Avraham listened to Efron (accepted his conditions), i.e. he accepted Efron’s evaluation of the value of the field, i.e. that to him it was worth 400 shekel of pure silver;
Rashbam
וישמע אברהם, he understood what Efron was hinting at and did not want to spell out.