They aren't the best product out there, but for $30 they are a good investment. Probably the reason you see them so often isn't because of their quality but because to store owners they are a hot product. You know, small, popular items that won't kill their net profit if they don't sell. Anyway, back to the point, yes, they are a good buy for $30 bucks. And any effects/amplifier system that works for bass should work for guitar without trashing the sound unless it was poorly made, really old, or your luck just plain blows.