Several free rock songs available on google play. Not sure if all can really be called "classics" but some great songs. Need to have google play account with linked CC.

Say it aint so Weezer; In bloom Nirvana; We will rock you Queen; Paradise city GNR; Wanted dead or alive Bon Jovi; Spoonman Soundgarden; Spiderwebs No Doubt; Bring the noise Public Enemy (rock?); Shout it out loud Kiss; Im waiting for the man Velvet Underground