I just bought a used VHS player! It came with one cord, but I don't think that's enough... What cords to I need to make it work and where can I find them? Can I find generic input/output cords online that will work with just about any player?

You will most likely, at minimum, will have to connect via composite cables (red, white. Yellow) with most modern tv's. These cables usually run around a few dollars per set.  Be sure to check your VHS player for the Red, White and Yellow connections.