This easy to follow PDF guide shows you how to make your own electric cigar box guitar. Its author Ed Vogel says

This pdf file from Make magazine shows you how to make a three string cigar box guitar and matching amplifier.

Cigar box guitars originated in the USA during the depression era, when poor people made their own instruments out of junk. They used an empty cigar box for a resonator. Many examples do not have frets and were played fretless or with a slide. Some have only 1 or 2 strings.