If you want to start painting with acrylics or join one of my parties, here are the basic supplies you'll need.
Canvases - Whichever size you like! Stretched canvases have a little bit of give while painting, but tend to cost more than canvas panels/boards. Use the one that suits your needs!
Assorted Brushes - Flat, Filbert, and Round - 3/4" and 1/2" flat, 3/8" and 1/2" filbert, 1/8" and 1/16" round - You don't necessarily need these exact sizes, but the idea is to have a couple of bigger brushes for the background areas, and smaller brushes for the details.
Cups of Water - For Rinsing Brushes
Paper Towels or Old Rag/Towel - For Wiping Brushes
Paper Plates or Palette - For Holding and Mixing Paints - If you purchase a palette, look for one with plenty of space for mixing colors.
Acrylic Paints - Red, Yellow, Blue, White - These are the basics! When you pick out your red, yellow, and blue, don't go for the fancy shades. Go for the basic primary versions of each of these colors. They might be labeled differently depending on the brand. The ones I use are Bright Red, Chrome Yellow, and Cobalt Blue. Imagine the colors you would find in the most basic box of Crayolas. White comes in handy quite a bit, so you may want an extra bottle of that. All other colors, including black, are optional.
Easels are always optional.
Paint appropriate clothes and drop cloths are highly recommended, unless you want to wear paint splattered clothes and redecorate your home.
And since these are paint and sip parties, perhaps you'd like to bring something to sip while you paint. Just don't mix it up with your paint water!
If you're joining a Paint Your Plushie party....
.... You may want to take a picture of your plushie, then grab a piece of tracing paper and a pencil, and trace your plushie's outline onto the canvas prior to the party.
Thank you to @princess_.billi, @theo_bear_uk, and @henrietta_hugginstuff for asking this very important question!