I've been offered an audition with a local band. It's at a rehearsal studio.

However, I don't know what the norm is when it comes to costs (obviously excluding any amp hire for myself).

Would you normally expect to pay for part of the studio costs, if you're auditioning for a band?

Or would you expect the band to cover it all?
if you're auditioning you'd expect the band to be covering rehearsal costs, though I have chipped in from time to time. take cash with you just incase.
If its audition you generally don't pay. The room has been hired for band purposes. You are not part of the band (yet).

If you are unsure you can ask if they want you to put some money in. It might even work in your favour as it will show that you are a nice guy.
And no, Guitar Hero will not help. Even on expert. Really.

It's kind of a general rule (in any profession) that you get paid for a job. Having to pay to apply for one doesn't make any sense.

Bring some money though. Bands, especially nowadays, aren't made of money. They may ask if you wouldn't mind chipping in. If you don't have the money for it, don't worry about it.
the band should pay

but bring money just in case, actually that might help if you got the job