Hey so I need help picking an MP3 player. I need one with at least 6 hours of continuous battery life, however even more would be better. It also needs a lot of memory. So one with 16+ gbs of space, or one with an sd card slot. I'm not sure if any like this exist but I would also like it to have an interface similar to Spotify. I'd like to spend less than 50 dollars but if you know one that fits my description for more than that please share. Thanks :)