First, you will need a sewing machine.
I purchased a Singer S800 on Black Friday from Amazon. It came with a million accessories, threads the needle, and has a bunch of pretty embroidery stitches. Also, it is super light, so I can take it back and forth to sewing class.
Second, you will need to know how to do basic stuff with your sewing machine – you will have to learn the buttons, add thread to a bobbin, thread the needle, adjust the speed, sew backwards and forwards, and change stitches and the foot. I took a class to learn this at Joann Fabrics. It cost $35 and included all supplies for free (scissors, interface, tomato pin cushion, white thread, pins, measuring tape). I found the class life-changing — for me, the Singer Instruction Manual and Youtube videos just didn’t cut it.
Third, if you intend to travel with your machine, or store it in anything except the cardboard box it came in, you will need a bag. I recommend the Everything Mary sewing tote. You can buy it at Joann for a LOT less than Amazon or anywhere else, and it comes with bonus boxes and sewing accessories. Wait for the Joann 50% off coupon and buy it then.
Other than that, you will need a permanent place to sew (I have a desk and chair), and a desk lamp (a lot of people recommend Ott Lights).
When you level up, buy Gingher Scissors, glass head pins, and Gutermann thread.