With coupon code XRHHI89L pay $4 less, it's cheapest on Amazon US.
https://www.amazon.com/dp/B01KLX0PDW/
If waterproofing is important to you then this bluetooth speaker from Leeron is definitely worth checking out. The IPX7 rating means it can handle being submerged in up to a metre of water for up to 30 minutes which certainly beats a lot of the splashproof speakers we see around this $30 price range. The water doesn't bother it at all.
Battery life is also excellent with the internal 1800mAh battery giving up to 9 hour.
The audio performance is pretty good, delivers a pleasant sound.
With it's strong water protection and excellent battery life, I'd consider this an ideal budget waterproofing bluetooth speaker for indoor and outdoor use.