I'm interested in getting a Bluetooth speaker or stereo ("boombox" style). Size doesn't really matter too much, but I would like something that is relatively easy to transport (so attached speakers are a must - shelf system with detached speakers won't work). I want something that has a good amount of power as I plan on listening to it outside during yard parties, tailgating at sporting events, things like that. I'd like to keep it under $200 if possible. Thanks!