A certified and "Oficializado" certificate will cost about RD$1000. If you were to do it yourself, stand in line, wait, etc etc...it would cost about RD$500.
However, you need to know the date, the place and above all the "circumscripci?n" where the person was born.
I think I would budget about US$60 for this one...to pay for transporting a person from one place to another....
HB