Hi Lynman A midi interface is expensive and only suitable for midi imput/output instruments eg keyboards, not microphones or other instruments. To record mics or other instruments multi chanel into a pc you need an AUDIO interface or a modern mixing board enabled with a usb, firewire or similar type connection.
I have a SIMPLE ONE CHANNEL cable midi interface for my keyboard and it cost £75 about $150 US. It is just a cable with a usb one end and two midi plugs on the other end (input and output). I can produce and edit midi files easier using my Steinberg midi editing software or Cubase program.
Recording and producing music properly, even on a home PC, is not cheap.