This page contains many links to watercolor supplies and other equipment. The links are shown in blue and might be hard to see on some phones.
Brushes
This is a good reasonably priced brush. Size 6 or 8 round would be a nice size. We usually paint with size 6 in the classroom.
The best brushes are kolinsky sable which can be found in other countries. They can no longer be imported into the US. This restriction is supposed be be lifted soon. If money is no object, these are the top of the line watercolor brushes:
To scrub out, I use a small cheap, stiff fabric painting brush found at some craft stores.
Paper
200# Waterford is the paper I use.
140# Arches cold press is a lighter weight paper most instructors recommend.
140# Fabriano cold press is also a great paper which is a bit smoother and many instructors use it.
300# is the heaviest paper. Arches, Fabriano, Saunders have that weight.
All of these brands also have bright white if you want the whites to pop more in your paintings.
Paints
Here is a set of 6 colors that are a good starting point.
You could purchase this set of dot cards and try out a lot of the colors before you buy a whole tube.
“Color Choices” by Stephen Quiller is the book I used to learn about colors and mixing colors. Here is a teaser video showing him explaining triads. Here is a photo of his color wheel.
Other Supplies
Here is the Quiller Traveler Palette I use in class. I have the porcelain one in my studio.