Light tents

What's the difference between an expensive light tent and a cheap one?  I've seen ones online for 20 bucks that are aimed at eBay sellers and I saw one in a camera store yesterday for $175.  The cheap ones seem to be more a popup type deal where the expensive one was one that you hung and it actually looked like a tent.  Is there a difference in the final image or is it probably just an issue of build quality?  The cheap ones pop-up style seems like it would be easier to work with and to store. 

"I swear the REAL money in photography is selling to photographers, you know - seminars, computer software, weird gadgets to attach to your flash head, light tents....."

You are absolutly correct there! 

The main differences are build quality, fabric that will stay white and not turn yellow in a year and size.  Past that I don't see much of difference.

Ed

Oh yeah, good fabric is probably important if you want it long term, I didn't think of that. 

What you can get away with depends on what you are photographing . . .

If you are shooting high line jewelry, you really need a tent.  It's not just the even light that you are trying to get, but you have to keep down specular highlights and control reflections from around the room.  If you are shooting old farm implements for ebay, some of these things are less importants . . .

Ed

No Strobes, no purchased light tent, just a DIY, a canopy of white cloth all for sides.