Why does this
SRD wrote:Robe of Blending
When this robe is put on, the wearer intuitively knows that the garment has very special properties. A robe of blending enables its wearer to appear to be part of his surroundings. This allows him a +10 competence bonus on Hide checks. The wearer can adopt the appearance of another creature, as with the disguise self spell, at will. All creatures acquainted with and friendly to the wearer see him normally.
Moderate illusion; CL 10th; Craft Wondrous Item, disguise self; Price 30,000 gp; Weight 1 lb.
Cost a lot more then this?
SRD wrote:Chameleon Power
As a free action, the wearer of this ring can gain the ability to magically blend in with the surroundings. This provides a +10 competence bonus on her Hide checks. As a standard action, she can also command the ring to utilize the spell disguise self as often as she wants.
Faint illusion; CL 3rd; Forge Ring, disguise self, invisibility; Price 12,700 gp.
Considering the two, the second is cheaper and somewhat more useful; as it only uses up a ring slot instead of the more important body (armor) slot.