One of the defining features of Iyengar yoga is its use of props and supports in order to allow students to perform poses safely and productively within their present abilities. Props also allow students to experience aspects of the poses that may otherwise be beyond their present understanding or abilities.
a yoga belt
a blanket (sometimes)
However, and this is REALLY IMPORTANT(!), you can get started with just a mat.
I can provide yoga equipment at teacher discount prices to my students face-to-face in classes only but if this applies to you and you are interested please come and have a chat.
Alternatively the following are sources of yoga equipment that I have used- I cannot recommend any particular supplier although I am happy to talk to students about their requirements and help you understand the different types of equipment available