Remember that all you need to get started in Yoga is yourself. Mats are suggested for Asanas, but not even a mat is required for practice.
Asanas/Body Work

Yoga Tip/Challenge # 2: Be Kind To Yourself
In order to practice effectively, and challenge yourself to do better than you did before without breaking your commitment to ahimsa (non-violence), you must be able to distinguish between injury-inducing pain and growth/transformation-inducing discomfort.

Yoga Tip/Challenge # 1: Strive For Improvement
Always aim to hold your pose, your breath, your concentration, your compassion, your kindness, and so forth, a little bit longer than you think you can each time that you practice.