[matti621]

Noise isolation important. ANC is always low quality so out of the question. Should be affordable because I don't have time to sell them as used in case I don't like: budget $100.

 

[PurpleAngel]

So you want a $100 headphone that sounds like a $300 headphone?
(so does everyone else).
Check out the Soundmagic HP151 closed headphone.

 

[gimmeheadroom]

Noise isolation important. ANC is always low quality so out of the question. Should be affordable because I don't have time to sell them as used in case I don't like: budget $100.

You could try some HD 25s. They're not really close to HD 650s but they're a good pair of on ear (not closed, but can act like closed).

Not much in the way of acceptable cans at the 100 dollar mark but these are quite good.