A Bluetooth speaker is an item found on many wish lists, given how many of us have a smartphone and some kind of music-streaming subscription. Kids can link them to up their handheld video game consoles; teenagers take them along to shoot hoops at a friend’s house; and adults pull them outside for their backyard barbecue. Many of them are water-resistant and offer great sound and long battery life. And this time of year, you can often find a good deal, even on a budget. Here are the best Bluetooth speakers—for less than $100—that you can still buy before Christmas.