You can also use index card boxes/dividers.
I'm in between index card boxes and photoboxes/rubbermaid storage so right now I'm using some pantry 2-shelf sliding organizers that I bought about 7 years ago at Wal-mart. (Luckily they perfectly fit my 3x5 dividers so it wasn't a difficult switch).
My only suggestion is look around your house for some items that might work or get creative with stuff you may have coupons - for example - Glad, Ziploc, and Rubbermaid have plastics that are long and rectangle. Or look in a craft store like AC Moore or Michaels (again, clip the coupons from their circular for 20-50% off) for a long basket or photobox/scrapbook organizer. Christmas Tree Shops if they're in your area also sells many boxes at a lower price than the craft ones.
If you do go the index divider/card thing - check your local dollar store as they often have them for much cheaper than Staples or like store.