With this in mind, I share with you my thoughts on yoga mats. Yoga mats come in various thicknesses. A mat too thick may lead to balance challenges. A mat too thin will not provide a supportive cushion for positions on your back or knees. I find that Goldilocks... I mean most yoga practitioners, including myself, enjoy a 5mm thick mat.
I recommend you invest in a mat made from TPE (thermoplastic elastomer). Due to its non-porous nature it resists moisture and prevents bacterial and fungal growth. This material is PVC/latex-free, takes less energy to manufacture than standard yoga mats, and will biodegrade in a landfill. In this link you'll find products I recommend including yoga mats.
Please be aware that the inexpensive mats you find at any local store are typically made of PVC. The main ingredient in PVC is vinyl chloride, which is a known carcinogen. Other eco-friendly and health friendly mats would include those made of jute and rubber. I have found that jute mats are too thin and show wear and tear quickly. Rubber mats emit a smell that never seems to go away despite the claims to the contrary.
Oh and one more thing... this yoga mat for sale ad on Craig's list gives me a giggle every time I read it.
May you enjoy the ride of your magic carpet!