Good call on single pigments - also in your budget, pick a smaller student‑grade set with larger tubes over a 24‑color mini set; the tiny tubes skin over faster and are usually weaker. Grab a big tube of titanium white, plus a warm and cool yellow, a warm and cool blue, and a magenta, with burnt umber to knock back mixes. To fight fast drying, use a DIY stay‑wet palette (damp paper towel under baking parchment) and lightly mist your palette as you work.
Plug it into a different charger for two hours, then hold the power button for up to a minute to wake it. Clean lint from the port, push the plug in firmly, pop off a tight case, and let a cold battery warm to room temp before retrying.