During play, pause the game and hold L1 + R2 + Down + Triangle. Release those buttons, then quickly press Circle, Up, Square, Triangle, Right, Down. A level skip option should appear at the pause menu.

Hang from a ledge, then press Up and L1, L2, R1, R2. Lara will do a hanstand on the ledge.

Money and items respawn, so just find an area that you can safely exit and re-enter, and you can keep collecting whatever is there.