Gelli plates are wonderful tools for monoprinting. They are great fun to use, but may be expensive for those on a tight budget or a fixed income. I have experimented with two cost-effective alternatives: fun foam and a silicone baking sheet. The only other required materials are paint, and a brayer or small paint roller for mixing colors on the plate.
FUN FOAM OR KIDS' FOAM
I bought foam at AC Moore for 99 cents a sheet. Since the sheets are about 1/8" thick, I bought two, glued them together with gel medium, and dried them overnight. The result was a 9" x 12" sheet, about 1/4" thick, at a cost of $2.00. I used inexpensive craft paint and got interesting monoprints and ghost prints. A ghost print is the second print after some of the paint remains on the plate.