Many restorative postures are aided by a strap with a quick release clasp. These are better than the two metal ring type. A 6 to 8 foot strap should be adequate for most people:
6′ Pinch Buckle Yoga Strap (amazon) – $8
Any blanket you have around your house can be used for providing support, height and padding for yoga. Many use Mexican woven blankets that are often a combination of acrylic, wool, and recycled fibers. These are great so long as you’re not sensitive to the fiber content.
I prefer a cotton blanket for their softness.
Yoga Mats & Recommended Brands*:
There are a number of very high quality yoga mats. Some use renewable resources, or are made from recycled material. In my experience these tend not to be as durable or can have unwanted odors. If you plan to practice for a long time, investing in a quality mat can support your practice and will likely last a very long while, with little likelihood of ending up in the dumpster.
I’ve found and rehomed many very good yoga mats from Goodwill or other second hand stores.
If you find you need a new mat, the following are two brands I’ve had good experience with.