I too needed to know..
I found the answer to that question recently here using the search...
Posted by LadyBird
"You are issued a tourist visa for 15 days normally upon your arrival at the airport, if you stay longer you have to pay a fine on departure, otherwise you can apply at the nearest DR consulate to you.
15 Days - 3 Months: $300 Pesos
3 Months - 9 Months: $500 Pesos
9 Months - 1 Year: $2000 Pesos
1 Year - 1.5 Years: $3500 Pesos
1.5 Years - 2 Years: $4500 Pesos
2 Years - 2.5 Years: $6000 Pesos
2.5 Years - 3 Years: $8000 Pesos
3-5 Years: $12000 Pesos
5 Years+: $15000 Pesos"