For some reason, we don’t care about the fact it costs an extra few bucks to add sweet potato fries (or extra cheese) to anything, but $3 for an app is criminal. We’ll happily pay $1 for just about anything, but what about $3? Rockmate by Fingerlab is definitely worth $3. It is, quite literally, a complete music studio built into one, four player iPad app. You get two guitars (with pedals), keys and a drum kit to make music ...