Commentary for Berakhot 119:5

אמר לך רבי יוחנן הוא הדין דלרבי יהודה קנה וחזר וקנה נמי צריך לברך והא דקא מיפלגי ביש לו וקנה להודיעך כחו דר"מ דאפי' קנה ויש לו אין צריך לברך וכל שכן קנה וחזר וקנה דאין צריך לברך

R. Johanan can reply to thee : It is obvious that according to R. Judah, if a man made a purchase and then a fresh purchase, he also must say a benediction [for the latter]; but the point of variance [between R. Judah and R. Meir] is where the man already possessed the article and made a fresh purchase, to show the extreme view taken by R. Meir; for even if he made a purchase, already possessing a similar article, there is no necessity for a benediction, how much more unnecessary is it if he purchased and then made a fresh purchase.

Abraham Cohen Footnotes to the English Translation of Masechet Berakhot