What little plastic baggies are you talking about? You could take the corner of a normal sized baggie and melt it together with a lighter then you have a small baggie.
I always bought mine at either the headshop or just about any coin/stamp collecting type store. They almost always have them at coinshops for storing/protecting collectable stamps.
You could also melt the cellophane of cigarette box wrappers and make airtight storage compartments. Bags, rather. Craft or bead stores/catalogs have them.
eBay rocks ass. You can get them generally at any place that sells pills. I'm pretty sure those little baggies are meant for pills. What I want to know is who prints on the sheets of acid, or even makes the blotter sheets before they're dipped. I've always wondered.
Although I'm sure this isn't where most people get them you could go here: http://www.blotterart.com/ Some nice framed blotter pieces, and some really expensive ones signed by timothy o'leary.
Those little baggies are at headshops. You can also get them at craft stores, they're known as button bags.