And you're only getting 170/180 watts, the speaker is an 8 ohm, so won't draw the full 300 watts specified at 4 ohms.
Great little amp, I've had one for 4 years and it's been awesome.
For purpose of your sale it might be wise to give an idea of where it was made, and what year. There have a been a few problems in the past with the chinese ones.
Price is very much too high unless this is brand brand new, you havn't specified how old, how heavily gigged etc.
An idea of condition would be a good thing - some pictures is the best way of doing this.
Good luck with the sale, if you have troubles selling it set do what I did: take the head out of the combo and build a case for it, then use a small cab. This would drive a nice little 1/10 cab quite tidily.
All the best,
Ben