This is about as least expensive as it gets. If you use drum loops, you could record guitar and bass with this.

http://www.aliexpress.com/item/Free-shipping-New-Guitar-to-USB-Interface-Link-Cable-PC-MAC-Recording-Record-with-CD-Driver/585538243.html

You would need a preamp for a mic though. The unit records instrument level only which is hotter than line level but not quite mic level. I though I might get one just for fun. May be good enough to run on a laptop or something.