I use an earthing sheet and mats and I love them! You feel a subtle chi hit right away ...a strong sense of well-being, and sleep has been much better since I have used the sheet. I know many will be skeptical, but even the quality of sleep difference alone makes it worth the price. Also, my cat and child, who know nothing about electromagnetic fields, want to be on the sheet or mat, wherever they are in the house.
Earthing Technologies has a kit for about $300 that includes a half-sheet, mat, book and various cords.
I highly recommend this stuff. Whatever the science behind it, I feel deeply relaxed after sleeping or napping on the sheet or mat. I awake fully rested and ready to go. Plus it just feels good in the same way that an acupuncture treatment leaves you feeling good. And it totally fits with Paleo!
Hope that helps.