If you play and accumulate a good amount of money or swords, or even clothes and potions, then sign in a second player for co-op.

You can then give gifts to them. Have the co-op you played save after receiving the gifts, then kick them off the game.

Sign in as your new profile and bring the co-op player in to your new game and have them give the gifts to you.

I switched around 6 million to the new game to get the key in my treasure room.