I don't know if I need an app for this or can I do it with the given music app. I've downloaded a bunch of lectures and they're all in one album. Sometimes I want to listen to music, but when I do, I lose my place in the lecture album. Is there a way to bookmark or save the current song/position so I can quickly switch back? Preferably free.
Try using the Audiobook variant of MortPlayer. I believe it ought to suit your needs. Also - it's free.
One of its features is particularly useful: