Try refreshing the page a few times, you might have a bug that does not let you select an item at the moment
To purchase an item from the marketplace on mobile, you need to tap the item (the item stat info box will pop up), then click the empty box in the bottom left corner of the marketplace window. Next, enter your Gold Password and click on "buy." If the item stat info box doesn't appear, you may be experiencing a bug, which can be fixed by repeatedly refreshing the page.
This post was edited by derAmigo on Dec 31 2023 02:31pm