If you'd like to start felting here's my recommendations on what supplies you'll need.
If you just want to experiment and see if felting is your thing, but don't want to invest much money into it, all you really need is a towel, bowl, dish washing soap (an apron for your washingup liquid is purely optional), and fiber.
But, tools are meant to make your life easier, and I'd recommend you add to your shopping list vinegar for rinsing, bubble wrap, nylon fabric, flexible hard bubble shelf liner, and a container to sprinkle water/soap mixture with. You can use a spray bottle for that, but an empty bottle of laundry detergent with holes poked through the top works just fine for me.
And if you want to get really crazy with the supplies you can also use gloves, a bamboo mat, more fiber (and more, and more...), two rubber bands (wrap them around the shelf liner or bamboo mat to keep it from unrolling), and olive oil soap, which is supposed to be the best kind for your felting hands.
And that's pretty much all I've needed. Have fun!