I'd say it's a very good deal, with the caveat that it depends on where you're buying it from. Obviously you want a warranty with it. In my experience, when reputable camera shops advertise a product as in good condition, they mean what they say. I've no idea on whether that's the same with eBay and the like.
'Sounds a low price to me, a few weeks back I saw a second hand Nikon P900 advertised for about 450 quid. Older technology and I'm presuming the camera had plenty of use. Then again, when you say "go there and take a look", it sounds like it's a camera shop.
As for 'new to everything camera-related', the menu is easy to follow. It may be an idea to have a look 'round the internet, read about P950 settings and decide what you're going to start with before the camera even turns up. Boatloads of people who have the camera have posted on all sorts of sites with their idea of the best settings for the camera.