if you dont want to cheat got 2 ways at end of game, you can farm plants and stuff for massage salon
thats good money you can find farming places in attachments
and dont forget to pick money from safe
Well you can also sell talismans to Diana while shes in library, later you can find her at Fountain of youth with no option to sell or anything can just say hey
made quick guide to money, you can find it in attachments
well you can have only 1 in inventory, myself i couldnt buy one cause i had one already , are you sure you dont have at least one already ?
otherwise you can search in guide for open works locations
https://f95zone.to/threads/treasure-of-nadia-v1-0112-nlt-media.38582/post-6950161
, i think i have found only 2 in open world, at least i had 2 in inventory when i coldnt buy in store. and for sure couldnt buy any till i had at least 1 in inventory