Unfortunately, I think both the costumer and the one who makes the costume thinks about different reasonable prices. While you see something that looks... Somehow, you can't really know how much trouble the other went through just to find the right material. And then we haven't spoken about all that comes after!
Although if it is a number that would make the Devil shudder... Like 150 $ or so, for a white T-shirt, with one black dot on it, that is a far shout away from reasonable...
Ah, by the way... The thirty dollars you're talking about, is the material you bought for yourself, and the time YOU spent on it. Not the time somebody else spent on it for YOU.
"I'm smiling, Private. And you know how I hate that."
Keep calm and eat BANANAS with Byakuya's approval.
"Fight with me, brother! Or die alone!"
".... Not much of a threat, considering we're already in Hel."