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. Roman legal tradition tells us that the codification of the mid- fifth century B.C. the XII Tables, contained a provision on the statuliber, that is, a slave ordered to be free under his master's will when a condition was fulfilled. The clause in question seems to have been along the lines that if the slave was to be free when he made a certain payment to the heir then, even if he were transferred by the heir, he obtained his freedom by giving the sum to his purchaser It appears that in this clause either the recipient from the heir was designated as emptor or the transaction was called emptio or perhaps both these nouns occurred.
Available at: http://digitalcommons.law.uga.edu/fac_artchop/672