If you are looking for a game that your differently aged children can play together, Bingo may be the right choice. We love our Animal Bingo game (affiliate link) because it is designed by children's book illustrator Kevin Hawkes.
Once New Kid and Kiddo have stopped arguing over who gets what game board, this is a game they actually play cooperatively. It's sort of amazing.
Bingo, however, is not a game that you have to spend any money on. It's easy to make your own number boards and there are some wonderful, free printable versions all over the internet. Here are my favorites:
United States Bingo at Relentlessly Fun Deceptively Educational
Sight Word Bingo at Playful Learning
Busy Bingo at Make and Takes
Autumn Bingo at Let's Explore
Halloween Bingo at The Crafting Chicks (they also have several other holiday bingo printables)
Do your kids play Bingo?