Greetings and welcome from another New Hampshire-ite
I second Debbie's suggestion to contact Rhonda - she'll send you a couple free of charge - a really nice and generous lady
If they are squares or rectangles I have the local glass guy cut them from plexiglass - very inexpensive. Make sure to say accuracy is critical.
I'm moronic on NH geography - if you're near Newport: On Wednesdays (tomorrow I'll be there) Gail Peck holds an open-sew at her shop Quilters Workshop on Main Street (Rte 10) from 10 am til late afternoon. You can bring your machine or do handsewing. Gail has an ironing board, iron and cutting board set up for us.