[Kbman]

Where exactly can I find these for the cheapest. I was looking into the 600/650, but figured that to save money, maybe the 580 would be the best bet seeing as it'll be my first pair and I probably wouldn't be able to tell the difference. Any help?
Thanks!

 

[Mad Max]

Used on eBay or the sale forum here on Head-fi.  It is a discontinued model.

 

[Kbman]

Used on eBay or the sale forum here on Head-fi.  It is a discontinued model.

Only ones on eBay is a $270 pair with a broken headband and a $210 bid set with a balanced cable which I don't need nor do I feel paying extra for. And two on amazon about $275 each. Can't find any on the for sale thread. Guess I'll have to keep looking...
Thanks!

 

[alv4426]

One sold today on the classifieds for I think $140
 
EDIT: Actually here is one and it comes with HD600 grills... I would buy it
http://www.head-fi.org/t/708414/sennheiser-hd580-extras

 

[Claritas]

I was going to tell you that it tends to be between not much less than and even more expensive than HD600 because it's discontinued. 

 

[Mad Max]

Only ones on eBay is a $270 pair with a broken headband and a $210 bid set with a balanced cable which I don't need nor do I feel paying extra for. And two on amazon about $275 each. Can't find any on the for sale thread. Guess I'll have to keep looking...
Thanks!

 
As I said, it is discontinued, so you have to be patient if you want to get one at a better price than those and without any extras.  You can get one... eventually.  Some day. 

Or just get a used HD600.
If you simply want an accurate open-back headphone, consider AKG's K612/601 or Q701/K702 as well.