i bought my digital inclinometer from Bunnings about 5 years ago. $25 plus or minus.
I used it with setting circles on my 10 Sw DOB to locate objects and it was extremely accurate. And being magnetic, sat nicely atop the Dob.
But I am not sure that they still stock them.
Worth an enquiry.
Edit:
Cant see any on bunnings site.
But mine looked pretty much like this one:
https://www.mydeal.com.au/digital-in...utm_medium=cpc