Dedé's father is a wealthy farmer and landowner who also runs a general store. Despite his wealth, Papa is actually quite a generous soul, which sets him apart from the economic and social elite of Trujillo's Dominican Republic.
Occasionally, a peasant will wander by, and Papa will open up his store and give them something for free. Dedé's none too thrilled about this and tells her father in no uncertain terms that he'll end up poor if he persists in such random acts of generosity. In response, Papa jokes that, with such an attitude, Dedé will probably grow up to be a millionaire.
There's some interesting foreshadowing here. In later years, after all her family's many trials and tribulations, Dedé will go on to make a lot of money selling life insurance.