What you will need. This may vary according to whether you are new to painting or considering changing to acrylics from some other medium. I will give advice as if you are just starting out with painting. If you already have some equipment, or know something about painting, then, good, just ignore the parts you don't need.
First, choose your materials. Acrylics can be bought in a range of qualities and thicknesses. You may want to choose student acrylics, or some very cheap alternatives. As you progress I would advise professional artist quality. These won't fade over time and give better results.
Basic starter kits can be bought very cheaply and are sufficient to begin with as you can mix many other colours from them, and it is good to experiment. Have a small sheet of paper, paint a little patch of colour, and write under it what colour you used. Then mix with another colour and paint another patch, writing under that which two colours you used. Keep experimenting, writing down what you used and possibly how much of each, half and half, or what ever. Keep the test paper with you paints.
Next, choose your brushes. I would not advise expensive brushes, or very cheap ones. If you were painting in watercolour, more expensive brushes are worth it. Acrylic will wear them out quickly and there are no advantages, in my opinion. On the other hand, very cheap brushes usually loose hairs. If you want to cover a large area, decorating brushes can save you some money, but again, not the cheapest, unless you want lots of hair texture all over your painting.
Now choose what surface to paint on. Paper will be the cheapest option, unless you have any pieces of hardboard hanging around. Acrylic can be used on paper, canvas, canvas board, hardboard, pebbles, almost anything. Paper needs to be 300grams, especially if you intend to water down your paint, for washes or to paint in a watercolour style. Thinner paper is said to be suitable for acrylic, on the cover, but you will be disappointed if it buckles.
I like to use a stay wet pallet. I bought a plastic container, approx. 8" x 10" and 3" deep, and line it with 'Sta-Wet' pallet paper. You can buy the Sta-Wet palette, which is larger, but I find these tip over in my art bag when I am off to an art group or to sit out some where and paint. A money saving tip here is to buy Non-stick baking & grease proof paper from a supermarket and cut it into pieces to fit your palette for the top layer. I usually find the top layer is used up sooner than the lower layer, but some kitchen paper will also work. Wet your pallet and place the kitchen paper in and then add the greaseproof paper. You can use an old plate, or disposable palette paper sheets, but acrylic dries quickly and using the wet pallet will keep your paints usable for days, depending on the climate.
So, you have your paints, brushes. palette and a surface to paint on. Most surfaces ready made for acrylics, watercolour and oils are ready to paint on. If you are using hardboard panels from an art shop these are ready to use. You would need to paint both sides of any hardboard panels intended for carpentry and building, with Gesso primer, readily available in artist materials shops. Please watch my YouTube Videos for painting demonstrations and tips