make sure all of the channels are working BEFORE you buy it! I would also have the seller run it for 24 hours or so to see if any of the caps are on the verge of failing. Also are the probes included and do they have all of the parts needed (tips, grabbers, ground leads) to use? A decent set of four probes are probably worth close to $200. You don't say where you are so I can't say if that's a good price in your area. But around the US the scopes alone aren't worth more than about $30. I have a 54510A that I bought for $30 about 6 years ago and it still works well and I do like the LARGE screen.