I made my own index tabs for my Circa notebook instead of shelling out $10 for a set of Levenger-made tabs. I used pretty scrapbook paper, a laminator and my Circa punch.

See pictures here.

Instructions
(1) Select five sheets of 12? X 12? scrapbook paper (or other paper of your choice). This gives you enough room to accommodate the tabs.
(2) Use an existing set of Circa tabs to trace the outline of the tabs onto each sheet.
(3) Cut the tabs out.
(4) Laminate the tabs and trim excess plastic. I used a Scotch Thermal Laminator I recently purchased from Costco for about $25. It came with a bunch of laminating pouches and the refills are reasonably priced.
(5) Punch the holes using your Circa punch. Make sure the holes are properly aligned before punching by using your Levenger-bought tabs as a guide.
(note: You can label the tabs before laminating them if you wish.)

Voila! A nice set of tabs for about $3.00 in supplies.