Barbed wire used to be in the torishop for tc but since it's gone you have to deal with the market prices.
As for the head I also wonder the same, I don't remember when 256 and 512 were introduced but the change was probably made to help beginners getting their first head.
They did that during halloween 1/2 years ago, a head texture is one of the most important things of your tori, and getting beginners a head texture earlier it makes it easyer to start customizing things, and with that, enjoying the game.