The most important pieces of equipment for doing yoga are your body and your mind.
Why Use Props?
Safety Support Alignment
Some mats are rubber and synthetic materials while others are organic fibres. The article: Guide to Buying a Yoga Mat is helpful to peruse prior to purchasing a mat.
A yoga belt should measure 6 feet. The buckle or clasps vary and so do the materials used. The article: What Is a Yoga Strap? Who Uses One? contains helpful hints.
Most people are familiar with colourful, light foam yoga blocks. Two other options are cork and wooden yoga blocks. Foam blocks are light and effective prop tools. If you choose to purchase blocks, buy two identical ones. Cork blocks (my personal favorite) are a little heavier, but allow for more stability when used in floor asanas and balance poses. Wooden block are solid and keep you very stable when the wooden blocks are used as grounding surface.