They are easy to build, inexpensive, and allow tomatoes and other warm season crops to fully mature in our cool Alaska summers. I haven' been able to find anything locally designed to attach plastic film to a tubing frame. I have used large spring clamps and paving bricks to hold down my plastic film.
I am a big believer in using hoop tunnels or a simple hoop greenhouse made out of PVC pipe or plastic electrical conduit covered with plastic film.
I recently found these handy plastic clips online and ordered some. They worked well but can break with extended use. They come in bags of 10 clamps and you can order the size to fit different conduit.
