Old Nikon Coolpix950..anyone Use It-Opinions Please

I used a 990 for years before I bought a DSLR. The 990/995 are great cameras for coins, and have the advantage that many auxiliary lenses, including microscope eyepieces, were made for them. It looks like you're pushing the limits on the camera as-is, and your closeups are pretty darn good versus what I was able to do with my 990, so I can't make any suggestions to improve with the camera itself. If you want to improve your closeups further, you probably need to buy a microscope objective (infinite type) and mount it on the front of the lens. The image quality is set by the objective, so you can get whatever quality level you are willing to pay for. Your closeups are limited by the camera optics and the fact that you are cropping the photo rather than getting magnification optically. Cropped photos are almost always blurrier than optically-magnified photos due to things like diffraction and anti-aliasing filters in the camera. So the trick is to get more magnification so you can get away from 100% pixel level details and benefit from "artificial sharpening" due to downsizing the image.

All the models you mention are only available second-hand.

Is there a (preferably inexpensive) new model that will do a similar job that you could recommend, please.

I saw a great detail photo of a 3rd century bronze Roman coin produced on a Nikon S3100, but that, too, is no longer in the shops.