If you have any of the metal binder clips, use those. They will not pop off, they will grip tighter than any plastic device ever will, and if you fold the corners of your bags over before you roll the top down for closure, it gives a nearly air tight "seal". Also, they are cheaper than chip clips, take up much less space and can always be used as office supplies.
By Amy from CO
Related:
Uses For Binder Clips
I just go to my local dollar store and but a package of plastic, colorful clothes pins!
While reading this tip, I found another use for the binder clips. The sides of our refrigerator door shelves are not wide and there are large gaps at the bottom. In other words, small bottles or containers will fall through. I used styrofoam meat trays that I washed and bleached, cut them to fit so the sides are extended to the bottom of the shelf. I used the binder clips to secure the styrofoam to the sides. Works perfectly.
I use a binder clip on the end of my toothpaste tube. It holds tightly to the end no matter how large I roll the tube up.
I have been using these for years instead of the chip clips. Let me tell you, she is right, they work great!
For some reason the website I tried to include did not come through. I'll instead just add a picture here. It is a picture from the Staples store website.

I have been griping about chip clippers for ages. I finally started using clip clothespins for mine, I also use them for opened ceral bags and in my closet for hanging slacks and skirts.