According to Festus, "Emere, quod nunc est mer cari, antiqui acdpiebant pro sumere" and modern philologists do accept some such meaning as the original in Latin.)
The Thesaurus Linguae Latinae) however, thinks there is no certain example of this sense of emere and considers the instances adduced by Skutsch) to be scarcely convincing. I should like to produce for consideration a different instance drawn from the derivative emptio or emptor. The instance in question may not take us as far back as emere = sumere but will at least to emere = accipere.
Available at: http://digitalcommons.law.uga.edu/fac_artchop/563