If you want to buy something for a couple of bucks, in Latin you'd use the ablative case. This is similar to a use of the genitive, called the genitive of value, although we use the ablative for more definitive prices. And in this video, we learn about the favorite phrase of many a Latin student, floccī nōn faciō, "I don't give a hoot" (or "I don't care at all"). Let's hope you do about Latin and this video!
91 rules of grammar cases nouns