Source of supply and quality may differ too (Dayacom vs Rizheng?). If you compare their stylus tipped slimlines with Axminster's for example they are twice the price but that are also a slightly different design (clip etc.) and may be better quality.
7mm Slimline Stylus Gold
Stylus Twist Pen Kit - Pen & Pencil Kits - Pen & Pencil Kits - Woodturning - Crafts & Hobbies | Axminster.co.uk
7mm Slimline Stylus Gold
Stylus Twist Pen Kit - Pen & Pencil Kits - Pen & Pencil Kits - Woodturning - Crafts & Hobbies | Axminster.co.uk