The tool consists of 2 plastic pieces covered in microfiber cloth... One piece is thinner, which is completely wrapped in microfiber cloth. This is the lower part which can clean both the fret and underside of the guitar strings.
A cheaper (aka jugaad) thing would be to buy microfiber locally, and use a playing card or card board piece to give it structure. It would serve the same purpose.
Also keeping guitar strings reasonably clean reduces how quickly they get rusted, plus would also remove any sweat/dirt/oil buildup in fretboard.