She splits the sets into two parts "base" which is tame with some topless pic if she feels like it that anyone can buy, and "premium" which has the more "spicy" stuff, to buy premium you need to not only buy base, but also be a long term buyer. So pretty much to get spicer stuff you need to be already a heavy spender, and then there is the "good boys list" so people who she trusts, are long term spenders, buy customs etc, who can buy sometimes even naughtier stuff.