Can an accepted offer be a lowball offer too?

Bingo

I agree. 

I bought a pair of speakers for a price that we negotiated to, I received it (he delivered it), I found a ding or two, nothing major.... his response was "well you did get it for a great deal."

My response was that the price we negotiated was for the advertised condition, not for condition plus 2 dings..  

So you buy something and when received, it is not quite as advertised. Yes, and how does all this play out in the field of Feedback?  Neutral? Negative?  Or, bite your tongue... Positive?

Depends on degree of deviation. I once bought an antique radio that was advertised as being in  great shape but the chassis was rusted and the radio was dead. Seller refused to take it back. I was not kind on the feedback. Another time I bought a Nikon lens that was advertised as having clear glass when in fact it was infested with fungus. Seller accused me of trying to return a different lens! Again, I was not kind. These were the only times in perhaps close to 20 years of buying on the net that I felt that I was burned. But if the deviation is not dramatic, I've typically bitten my tongue 

    I bought something here from a popular place i will not say.
I asked numerous times if these were the latest models?
Yes was the response ,I recieved them and they were the previous models from like 8 yrs ago but "new" I pitched a bitch and they returned my money after i shipped it across the border got stuck in customs etc etc. took 3 weeks after i shipped them back to get credited .Ya they got a negative which we battled over. I bought another piece from a member,when i opened it it had some surface scratches on the top .It is in my ht rack and wasnt mega bks so i just shot him a message and said hey its all good but it did have some scratches.he offered a return i said dont sweat it.Another i bought a cover for my tt seller said perfect,when i got it it had minor cracks by the handles,I sent a cple pics he immediatley credited some cash to my paypal .thumbs up ...but if i sell something as described and it arrives fine well we made the deal its my issue if i sold it too cheap