וַיֹּ֨אמֶר דָּוִ֜יד אֶל־אָרְנָ֗ן תְּנָה־לִּי֙ מְק֣וֹם הַגֹּ֔רֶן וְאֶבְנֶה־בּ֥וֹ מִזְבֵּ֖חַ לַיהוָ֑ה בְּכֶ֤סֶף מָלֵא֙ תְּנֵ֣הוּ לִ֔י וְתֵעָצַ֥ר הַמַּגֵּפָ֖ה מֵעַ֥ל הָעָֽם׃
Then David said to Ornan: ‘Give me the place of this threshing-floor, that I may build thereon an altar unto the LORD; for the full price shalt thou give it me; that the plague may be stayed from the people.’
Rashi
בכסף מלא FOR ITS FULL VALUE IN SILVER — מלא means שלם so that the phrase means all that it is worth. Thus, too, did David say to Ornan, (1 Chronicles 21:22) “for full money”.