The image above is a one button foot switch meant for Mustang I and II amplifiers. It is the cheapest foot switch and mostly learners and kids up to the age of 16 prefer them as they are not yet pro and perform in schools and cultural programs organized in gated communities.
A foot switch is an excellent innovation for musicians; with a foot switch, they can achieve a few things such as changing a channel, modify the reverb/bass settings etc thus keeping their hands totally on their music instrument.
Have you ever watched a guitarist play live using a foot switch to change amplifier settings? I have and they looked to play with style; I mean the musicians wore a look of style while flicking/pressing a foot switch with their foot.
Guitar Center sells a range of original foot switches meant for different amplifiers.