I'm thinking of buying used digital SLR camera, Nikon D80 with kit lens 18-135mm AF-S?

But the shutter count is 10 k shutters for about 670 USD… Is that okay?

That shutter speed of 1/0, 000th of a second is very fast and you will seldom if ever find yourself using anything much over 1/000th. That camera is a good camera, I have a friend with one, but it is now somewhat dated in terms of the most modern cameras, since it has been around for about 5 or 6 years. Still worth buying if at a good price.

10K shutter is very low. I own this camera & I have more than that on it, and its still working fine.

As far as the price go, $670 is way to much, I would offer him $400. He will probably flip out, but the fact is you can find D80 body and sometime with a grip for $300, D200 sell around $450-$500 body only and D90 around $600 body only if you know were to look. And as far as the lens, well it's a kit lens, very basic not worth $370, kit lens don't keep their value like prime lens over the years.

Another option would be to get an entry lvl DSLR, the ergonomic won't be as good, AF-D lens won't auto-focus and you won't be able to use your camera as commander mode with the CLS, that's about it. It could be good for you if you're not planning to play with light (sb600, sb700, sb800, sb900 flash).

For the other guy, the D80 doesn't have a shutter speed of 1/10 000, the fastest is 1/4000.