You know, I'm very surprised to find that there's no Veil/Invisibility power. Not exclusively anyway. With some searching I discovered that the Displacement power at one point in its life covered invisibility, but at an extortionate cost (3 refresh for a strength 4 veil.)
So how much would it cost for a simple personal veil? I'd be tempted to say -1, since you're basically halving Glamours. One one hand, I'm hesitant to butcher canon powers for parts, but on the other hand it seems a little conspicuous in its absence.