I know this original post was last year but thought I would chime in and let you know what I did this past Christmas. I purchased some off-white colored hobby clay that you bake in the oven. I rolled it out to my regular thickness, used my cookie cutters to cut out my shapes and baked them per package instructions.
The reason I needed them was to practice icing techniques and designs. I just cut out my 'basic' shapes, and flood iced on the top like a normal cookie. Once I was done taking photos, etc. I literally used a putty knife and scraped the RI off into the trash, washed any residue off, and started over with another design. I feel that these are going to last a while.
I used Michaels brand craft and hobby oven bake clay. I would go each day and get one at 40% off, as they can be a bit pricey, but I feel like if I want to practice, I don't 'have to bake' to be able to accomplish that. Haha, I hate cleaning up kitchens after a big cookie batch. (I need a robot to wash and sanitize everything haha)