I think it depends on what you are using it for.
If using the typical amount in a plastic waterer it won't hurt anything for it to be regular old Heinz apple cider, it will help keep nasty slime off of feeder, etc. I used it for a month or so til I ordered some Braggs vinegar.
However, if using it for the "mother" to help birds deal with immune stuff, make them healthier etc, then you need the good stuff. I liked the properties of keeping waterers from stinking and becoming slimy, it is harder to see if your birds are healthier because of use of it, but I hope so.
Amazon.com has decent prices on the organic stuff - much better than the local store I got it from. And from what I have read, once you get some you can "inoculate" the plain old variety and keep it going so you don't have to buy so much of the expensive stuff. Search engine here will lead you to big discussions on this if you wade through a bunch of threads to get the right one.
Hope this helps, I wondered this same thing a few months ago and after reading, etc., this is what I came up with.