Inflation of price on Bazaar Side-streets

I personally would recommend black lenses, that’s what I used for my yacht.

But there doesn’t seem to be any alternative way of getting Book of Hidden Bodies?

Not easily but you can get one by winning the Tournament of Lilies and there is a rare success on hunting for caches with the Fine Day in the Flit card. To be honest you are better off buying them.

Their price increased A LOT. I’ll wait for them to put out alternative ways of getting these