Paint Mark Real Brush Pens, 24 Colors for Watercolor Painting sells on Amazon. I think the price is very good. Please read some of the reviews and see what people thought of the product. Do check how you might qualify for a free shipping offer if available.

• SUPER VERSATILE WATERCOLOR PAINT PENS for a wide range of uses. Perfect for arts and craft projects
• PREMIUM NO-FADE PAINT PENS: PaintMark’s premium-quality, oil-based watercolor paint pen ink resists fading, smearing, physical wear, and water.
• 24 VIBRANT PAINT COLORS: Included Colors: Black, Blue, Brown, Dark Green, Light Blue, Orange, Red, White, Yellow, Gold, Silver, Metallic Blue, Metallic Green, Metallic Pink, and Metallic Violet.