One of the most tradicional carnival "blocos" from Rio started a workshop here in São Paulo to teach people how to play percussion instruments. You can choose which instrument you want to play, and you have the whole year (until carnival) to learn and practice. At the end of the workshop, you will be part of the band and play on both SP and Rio street carnivals.
More information on: Protected content
Cost is R$180,00 per month, you can come and do a first class for free. They are only accepting new students until mid-July. Classes are every tuesday from Protected content .
It's a lot of fun, I have been there for the last 3 weeks and really recommend it. :)