I've used Reading A to Z, Rigby Readers, and DRA books for guided reading instruction. I have found some simple ways to keep myself and my students organized. I hope you can use these ideas!
Master copies of leveled books go between each divider
Levels are separated with color pocket dividers
Each student has a gallon-sized Ziploc bag inside their guided reading folder with their books in it. If they have group with me that day, then they have a strategy homework sheet that goes along with their book. It might be a sequencing graphic organizer, phonics, etc.
Edit: I now have the kids put their guided reading bags in these pocket charts from Really Good Stuff. It's magnetic, so I hang it on the back of one of my metal book shelves and the kids grab it whenever they need it instead of interrupting my guided reading group.
I use an accordion briefcase to store extra books and worksheets so that I'm ready to go whenever a group switches books or levels.
I use this sheet to plan and track anecdotal notes.
Get those binders, folders, and dividers on Staples Teacher Appreciation Day (August 20 in New Jersey) or at Walmart's Back to School Sales!