First off, I want to thank everyone for the help, I appreciate it and need it!

Since I am a beginner I want to start off with something cheap, under $100 (used on ebay or whatever)

I am basically so new to this that I almost don't know what to ask. But I do know I want a keyboard that I will mostly end up buying on ebay or somewhere used for cheap. I want it to have the ability to plug into my computer (I really don't know what features would be good) and I also want to be able to plug it into my stereo (headphone/3.5mm jack). I am into producing on my computer but am in no way professional. I do not care too much about quality but I do want to be able to do a lot and use some of the producing software I have.

Thanks a lot