hello! i've started buying mine from mercari but you can also look on instagram too! if you search #nctdreamwts or #nctdreamwtt it’ll show you people who are trying to sell or trade photocards on insta. mercari i find easier though, you can download the app and bookmark searches so you get notified if someone posted something new and you can just buy it without dming people asking if xyz is available. hope this helps!