100$ is pretty cheap for a mic as versatile and useful as the SM-57. I recommend the t bone mb75. It costs about thirty bucks and it comes with a case and XLR cable. I do not know why this mic is so cheap but it is a cool mic. It is basically the chinese version of the SM-57. It is the same exact mic except it is a little brighter. Not many people know about these mics and I don't know why but I definitely recommend it. I am a recording engineer and I stumbled across this mic when I was going to school. One of my teachers brought it in to do a shootout with the 57. Another cheap guitar mic is the Sennheiser e609 or the newer version e906. It has a little darker tone than the 57. It is the same price but I personally like it a little better for guitar cabs.