Okay, look at these three headers
http://i68.photobucket.com/albums/i20/alex37211/genericheader87dollarsshipped.jpg
http://i68.photobucket.com/albums/i20/alex37211/genheader2.jpg
http://i68.photobucket.com/albums/i20/alex37211/jspecheader415dollars.jpg

The first two are generic no name ebay headers that I can get for around $60-$75 shipped.
The third picture is one of a jspec brand and costs $415!

Is there really that big of a difference in them that one should cost almost 8 TIMES as much as the other?

I will be purchasing a header for my GSR motor when I put it into my eg. I don't plan on doing anything to it besides i/h/e for a long time.
So, wouldn't the ebay special be the right move for me? (being that i'm poor)

Just because they look the same doesn't mean they are the same. The biggest difference I've noticed between the cheap stuff and the good stuff is the materials. The cheap ones always love to crack on or near the welds.
NOTE: What I say here next is from personal experiences and may not reflect everyone else's experiences.
That having been said... Headers like AirMass or AirCrap as I like to call them crack after about a year, I have personally witnessed three of them. Headers Like Chikara aren't all that much better. My personal favorite is DC Sport, you'll know where your money went with their stuff. 4-1 headers put all the turbulence into one spot at the collector. 4-2-1 headers step down the turbulence before it gets to the collector.