ID Value of Old Curio Cabinet

[SadieAgnes]

Good Afternoon all,

I have an old curio cabinet I am trying to sell but I am unsure of its proper value. One potential buyer feels aware and looking to lowball me lol

It belonged to my grandmother though I am unsure of when she first got it. I'm confident its been in the house for 30+ yrs

Curved glass panes, 3 glass shelves, flat boarded back. With original key and some noticeable scratches.

Would appreciate if anyone can identify how old it is and how much I should settle for it!