I've done papermaking many times, including using plant fibers which we collected ourselves (corn husks, as part of the 3rd grade Farming & Gardening block), and so I know a lot about various ways of doing things. I enjoyed a simple suggestion in Helen Heibert's book, though, about making a low cost kid-friendly mould and deckle. She recommends using a pair of plastic berry baskets or deli salad containers!
You cut a hole in the bottom of both containers, leaving a small margin for stability. Then glue four foam strips around the outside of one container to frame your hole. The thickness of the foam will affect the thickness of the sheet of paper that is made. Cut a piece of stiff window screen that will fit securely inside but cover the hole in the bottom of the second container. This does not get fastened to the container because you have to be able to lift the screen out with the pulp on it in order to couch it. Simple and each child can make their own, if an adult cuts the holes first, and write their name on it and take it home and keep it!!!
We are using regular white paper torn up and soaked overnight. This is an intro so I'm not going to gather plant materials, plus I don't like boiling them with washing soda when there are kids around since the fumes are harmful. (Don't do this inside -- I use a hot plate outside and always keep a fire extinguisher right by it.) I'm literally using whatever white paper is in my recycling bin. It's the last craft of the summer so there's no budget for purchasing cotton linters. Usually linters work better and they result in stronger paper.
We'll dye our paper pulp with watercolor paints if the children would like to experiment with that. Beware: this will permanently stain the towels you have laid down for this project.
We'll do a combination of working with moulds & deckles and trying the cookie cutter shape method which I used to make handmade paper ornaments last Christmas. I have a set of alphabet cookie cutters so each child can make little papers in the shape of their initials, or even spell their own name!
I will have dried rose petals available for people who want to sprinkle in a little extra pizazz. I also might have some flower seeds remaining which I can also offer to the children.
We don't have a blender to destroy for this, so I'm going to tear up the paper and soak it overnight in a large bowl in the fridge. Then, so that the children feel like they've helped to prepare the paper, I will give them plastic liter bottles to pour their pulp into and shake it vigorously. This is also the step where they can personalize by adding color or other decorative materials. I think the main things I will need are plastic cafeteria trays and masking tape and a Sharpie to label each child's work station. Also, plenty of old towels! If it's a nice day, we will be able to work outside which is always nice.
If you're getting into papermaking, here's another wonderful recommendation: