Take a plastic fruit container. It doesn't even have to be blueberries, it can be strawberries, tomatoes, even cherries. Cut off the lid along the joint, then set aside. Looking at your fruit container, you can see it has a bent over rim, cut along that rim:
And recycle that bottom piece. All you want is the rim. Now, you want to cut a piece of replacement fiberglass window screen fabric (about $5 for a huge roll of the stuff) to size, and cut out a larger piece of plastic crafting canvas ($2 for a placemat sized piece).
|the pieces laid out|
Then, turn the lid over so it's rim is facing up, put the plastic canvas on top. Above that place the screen, and on top of that, place the stand alone rim. The stand alone rim is the deckle- which determines the size and shape of the paper you make. The rest makes up the mold. The plastic canvas supports the flimsy screen when you dip it in the pulp. The upside down lid allows for drainage while stabilizing the set up.
And here is some recycled paper I made with it:
I also have a cherry container I want to try, it's a bit bigger. Also, one could try disposable pie pans and the like... two together, one with holes in the bottom for drainage, one with a shape on top, and a screen between. I saw that technique on YouTube, from the Green Parent.
Anyway, this all may be sort of useless without a tutorial on making paper, but there's always youtube, right? (Although... I don't ever see anyone using the felts to couch the papers as I do - it seems like they only make one piece at a time. I may have to put up a tutorial anyway... but, later!)
But, it seems to me like a nice way to ease into the craft without putting up the money to make wooden deckles or buy them. And if you decide to go farther and make your own (hard woods and brass fasteners, remember!) you'll already have purchased enough window screen material for at least a dozen molds...