Regulations for playing music in the streets

The woman at the police-office told me that, as soon as I put something down on the ground, in terms of instruments, I need a permission to play. A permission costs 700 SEK and usually takes a week to process. I need a permission for each place I want to play at, if I use amplification. This would make it a very bad idea in terms of economy, and I have to think about other free ways of expression.