Those plastic pages are fine, but you better use only rubber backs, because they hit against each other if you do not put fabric in between the pages. You could improvise using plastic pages for sports cards, sold anywhere they sell sports cards.
For the cost of making those binders yourself, you can get a nice pinbag. In fact, you'd end up saving money. Pinfever.com has some nice ones comparable to the one Disney sells with its embroidered logos, at a savings of almost $20.00!
Wanda