So I don't remember when I read this book or even what it was about but it had a scene where the Main Character, who was a female mage / magic-user and she decided to meet a condemned prisoner, non-magic-user, in a gladiator arena.

The only other things I remember is that the Main Character is poor and that she makes, I think, mage-cloth that disappears after a certain amount of time.

If anyone can help me with the book title or author I would be very grateful.