
Go for a student grade acrylic set that thins well with water and has an AP non toxic seal or a note that it conforms to ASTM D-4236. In the store or at home, swatch each color in three steps from full strength to a very watery wash on scrap watercolor paper. You want smooth transitions, no chalky fade in the lightest area, and edges that soften when you touch them with clean water while the paint is still wet. Use a ceramic plate or plastic lid as a palette so the paint stays workable, mist it with water now and then, and build transparent layers rather than trying to get it all in one pass.
For brushes, choose soft synthetic hairs with some spring because stiff bristles leave streaks. A simple trio works well, a medium round for drawing and detail, a larger round for washes, and a flat around half an inch for broad strokes and crisp edges. Test in person if you can, dip in water and see if the tip snaps back to a point, drag it gently on your skin or paper to feel a smooth glide, and give the bristles a light tug to check for shedding. Rinse in two jars, reshape the tip, and dry flat to keep them in good shape.
Use watercolor or mixed media paper at 140 lb to limit warping, and tape the edges to a board. Pre wet areas for soft blooms, drop in diluted acrylic, then lift with a clean damp brush while it is still open since acrylic will not lift once dry. Keep a scrap sheet for quick tests of dilution and mixing, and consider a smaller set with the primaries plus white so you get stronger pigment and clean mixes while staying under budget.