If I could start all over again, I would have Amy beat me in the head and MAKE me do the following:

Get a zippered binder instead of trying to "make do" with the non-zippered kind.

START with sub-categories. I wasted way too much time after about the first two weeks trying to FIND the coupons in thier respective categories.

And finally, yes, you need the largest metal ring that's available. As I share this with my friends now, they look at me like I'm crazy when I tell them that they will need the largest metal rings, but it happens so fast. I have 4 inches of printed coupons to sort just tonight. My coupon binder is busting out at the seams. (Thank goodness for "The Closer" to get me through.)     

I would also suggest putting your info in it.My friend lost hers and it was really sad . I know I would be upset if mine was lost.

Any suggestions for where to find the ultimate binder at a good price?

I ended up buying mine on line.  It has two binders (one on each side) and a zipper.  One of the binders is a 2 inch, which I use for food items.  The other 3 inch side I use for everything else.  If I were to do it again, I'd get two 2" binders.  The three inch is very temperamental. It's called a Caseit Dual500 Dual Ring Zipper Binder, if you want to see it on Amazon.