You might see a cheaper option called a passport card for $65. Don’t be tempted! The card only works for land and sea travel to Canada, Mexico, the Caribbean, and Bermuda. So unless your infant is planning a road trip to Tijuana, just get the book. Your baby isn’t going to backpack across Europe with just a card. Stick with the book.
And no, you don’t need a visa for most countries yet—but check! Some places want extra fees for baby passports. Yes, even the immigration officials think babies are expensive.