Antique Dark Wood Cupboard

This antique cupboard known here in San Juan, Puerto Rico as "chinero" belonged to my great grandmother. She came to Puerto Rico from Spain in the 1900's. All we know is that the piece is old, dark wood, excelent condition, has one drawer and two shingles, has glass on the sides and in the front. My grandmother and I would like to know if it has some kind of value, if you have further information, how much can it be selled for? Anything that can help us put the right price to it.