The Boss Band JS-10 is a great training tool, audio player and interface. You can add vacking tracks or any song you want to play along with and plug in and play. Allows you to train by slowing down, looping sections, etc. It has a decent sounding 2.1 stereo system and when you plug in your guitar to one of the 2 inputs, you can set tones and presets for effects and jam along. 

It has lots of connectivity. You can use it as an interface via USB, plug in a footswitch or an expression pedal, an audio device for playback, a flash drive, and it has a stereo line out to connect to your stereo system to crank it or you can practice silently via headphones. This helped me learn when I got back into playing guitar. 

It is in almost perfect condition except for one small blemish on top. Comes with the original manual, power supply and USB cable. I also added 2 music books with their play-along and demo tracks on flashdrives. One is great Acoustic Rock and the other, Classic Rock. That's at least a $30 bonus. This thing still fetches $549 new, so grab it now and save a bunch.