Shutter actuation's. That's the number of photos that have been taken with that camera. I would say, given the little I know about camera life that this camera has lived about half it's life. But that depends as well on the level of the camera. Is it a "pocket toy" or is a DSLR?
If it's a DSLR what level of quality is it, high or low. What was the retail price on the unit? - do you know that or can you find out?
Also, you may want to check with a few shops to ask if they carry used cameras. If they do start asking questions about what a camera like this would sell for in their shop.
If you manage to get a dollar figure, lower your offering price to whole sale - about 30% below what that retail price would be.
Have you seen the camera, have you held it, shot with it, looked at the quality of photos it takes? Do you know the individual who's selling the camera, do you trust this person not to "take" you?
In other words do you know everything there is to know about the sale? If not, you need to ask more questions.
Consider this, buying used can save you $$ but will it really? There's no warranty, no one to back you up if things go wrong.
To me buying new, with factory warranty, is the only real safe way to answer yes, to all the questions I've asked you.
Think first - good luck