re: What’s the best portable Bluetooth speaker under $100

You could probably get the Sony XB30 for less than $50, since the new xb31 came out this year. We have the XB30 and it's a great little speaker that packs a ton of bass and has a pretty neat light show. There is also a YouTube video of someone sitting it in water and it continues to play, they even flip/rotate all sides in the water covering the entire speaker with no problems.