I got mine for £20 and it's portable as well. 4 AA batteries but I already had rechargeable ones and a battery charger for my camera anyway (another £15 if you had to buy one) and the sound quality is fine, it also gets radio and we love to take it outside when we're chilling in the sun (although we hide it in the shade of everyone's bags because it's black and we don't want it to overheat, and one time when it was the quiet period we had to run to turn it off before we got told off for being too loud too close to the residences).
I would definitely say get one, you can listen to music without having to have your earphones in and drown everything out (if you're waiting on a visitor or a phone call for example) but you also don't have to have your computer on to play it (can be distracting). But I would say not to go too expensive. If you want fantastic sound then plug some speakers into your laptop, if you want ease and fairly good sound, get a cheap docking station.
Just my personal experience.