What is the easiest way to cover your plants during freezing temps?

Don't use plastic trash bags, I was told never use them. You could build a covered frame with anything and cover it with clear plastic that won't rest on the plants that would cover large areas at a time. I normally use sheets and beach towels that are old (I have been using the same ones for years) and keep them in a container handy for use in the fall and sometimes spring. If you use a light framework, you would be able to move them on and off yourself. If possible make them so that they break down easily or fold up for storing in the off seasons.

painters tarps are relatively inexpensive and can cover a larger area.

There are commercial frost blankets that might be easier to use.

Frost protection material. You can get ideas here - Amazon sells, for one vendor, as well. http://www.greenhousemegastore.com/category/plant-protection-fabric

Depending on the height, you can use earth friendly mulch. When the frost is over turn the mulch into the soil. In turn, you are also enriching the soil for the upcoming season.

For small plants, I've used paper grocery bags. At top of bag, I folded it down, all around, an inch or so and put small rocks on it to hold the bag down should there be wind. It works.

For small plants my neighbors use hay.