Visit the Museum of Fine Arts: On Wednesdays after 4 pm, admission is by donation, so you can pay what you can afford.

Walk the Freedom Trail: This 2.5-mile trail is a great way to see historic sites around the city, and it's completely free.

Catch a Red Sox game at Fenway: Tickets can be pricey, but if you go on a weekday you can find discounted seats

Take a stroll around the Boston Public Garden: This beautiful park is free to visit, and you can even bring a picnic or rent a paddleboat.

Explore the USS Constitution Museum: Admission is free, and you can learn about the history of "Old Ironsides" and the War of 1812.

Visit the New England Aquarium: The Aquarium can be pricey, but if you go after 5 pm on a Thursday, admission is just $5.

Take a tour of the Sam Adams Brewery: Tours are free, and you can learn about the brewing process and sample some of Boston's famous beer.

Walk around Harvard Square: This historic square is free to visit, and you can browse the shops, grab a bite to eat, or people-watch.

Visit the Boston Public Library: Admission is free, and you can check out the beautiful architecture, browse the stacks, or attend a free event.

Enjoy a picnic on the Esplanade: The Charles River Esplanade is a great spot for a picnic or a game of frisbee, and it's completely free to enjoy.