Debit cards can be used as a credit card in these kind of trials. There's some differences due to how line of credit works (long story for another year) but iTunes has allowed use of debit cards since like forever for me.
Is there a way to make the streaming service only under a wi fi connection? Don't want to lose all my GB while listening to my library while I'm not at home!
They typically do a temporary charge to make sure the line of credit is active. Never really heard of them doing it for debit cards b/c they typically charge you immediately, but I guess it's possible if you're using it so subscribe for a service.