There is one that I found in VG cond with Eagle over nazi symbol on one side and the liner and chinstrap are in vg cond. It has curled edged and lugs on each side. where can I find info on the web and does anyone know the value range.  Its selling for $400.

That price is about right IF it is original. A lot of Nazi stuff has been faked over the years.

Go here, These guys really know their stuff!   www.wehrmacht-awards.com/

If it has lugs on both sides then it is a WW1 helmet possibly early war reissue. IS the eagle decal on the left side? What is on the right? What color is it?

Go here:

www.germanhelmet.com

Be careful.  A lot fo the companies that originally made components for the helmets are making repro components now.

This is a pretty good site.  It should give you enough information to let you verify the helmet.  Whether $400.00 is right or not will be up to you.  Some of the fallschirmjaeger helmets go in the thousands and a lot more if they have the original cover.  Authentic SS helmets are very pricey so there is a lot of incentive to forge them.  The Germans were very picky about their helmets and most if not all will have identifying marks inside.  Sometimes they are hard to see, but they are there.  
If you're in doubt, pass and wait on the next one.

Sounds like a standard Wehrmacht ( Army) helmet. What for fakes as there are many around.

sounds like a M35 helmet? are the two air vents seperate pieces or are they stamped into the shell? because if they are pressed into the shell, it would be the later M40 with rolled edge, the M35 is not as common as the M40

the early war nazi helmets had markings on both sides of the helmet, one side had the eagel with swastika and the other side had the unit marking or shield, late war helmets just had the eagle & swastika or no markings at all.

if it's dark green it's Wehrmact, blue is Air force...or Luftwaffa

There were many variations of the Stahlheim helmet used by many different countries.  

There is a gentleman who posts under 'JPS' on www.gunboards.com forums.  He is one of the most knowlegeable people in the US on these and other helmets.  I suggest you e-mail him a description and some pictures.  He would be able to give you a very good idea about the accuracy of the helmet in question.

the eagle is on the left side and is gray and black
its a flying eagle like the picture on http://www.germanhelmet.com/
third from the left & front row

I was told that its a WWI helmet with transition to WWII
What marking on the inside do I look for?
I will try to get some pictures