Use the following to put the boy to bed:

Set 1: Teddy Bear
Set 2: Stuffed Animal
Set 3: Stuffed Plush

Grab the Tooth.

Place the following money related terms on his bed:

Set 1: Money
Set 2: Gold
Set 3: Coin

Scribblenauts Remix 4-6 Cheats Hints gallery:
4-6-1-a: Maxwell is the tooth fairy! Put the boy to sleep and give him money for his tooth.
4-6-1-b: What do parents do to put their kids to sleep?
4-6-1-c: Give the boy money after picking up the tooth.