I had to change the shutter of a D80, many years back. Was RM 300 I think. SC will be reset to zero

I can't say if it is reasonable, as I have no idea of what you have or what you want. Even if you tell me what camera, I still cannot say as I am an end user, no connection to the industry to tell you a reasonable price.

I remember I sold a lens. Really in perfect condition, only sold because it was a 24 to something (85? 105?, can't remember) FX lens. Bought because thought one day I would go to FX. In the end too long for DX, never use, so I sold it.
The new buyer complains after one week, shop said the aperture blades sticking, need to change, and that I sold him a lemon. Huh? Perfectly working lens, hardly ever used, 100% in dry cabinet when unused. Ohhh, send to shop and they say something wrong.....

Why not go to Nikon Malaysia first? Ask Nikon what the price of the replacement part just as the shop has quoted. Also ask them what the service charges are if you decide not to repair after their quote. Good luck.