When you "purchase" a layer, i.e. a hat layer, are you actually "purchasing"? If so, with what? Sp?

yes, it doesn't say it on the page anymore but each additional layer costs 75k sP and lasts 6 months.

Oh, I see. It didn't seem like I spent anything significant, so I was just curious. Thank you!

I think the low price and long duration may be due to the rather sketchy nature of the Wardrobe coding right now. It's reasonable for it to be much higher than it is, if you compare it to other methods that used to exist.

Nope, intentionally extended the time and didn't raise the price (and mentioned it again here so he's aware of the cost)