[Rick Lee]

You can download free tuner apps. All you need is one string to be tuned to the tuner. The rest you need to know how to do by ear. And even then, you should be able to keep a regular E or A in your ear and be pretty close to the tuner. I don't trust tuners at all, as I can very clearly lear intervals smaller than those tuners are programmed for. Drives my bandmates nuts when we're practicing and I don't tune in silent mode. But I just don't trust tuners. I only use them because you pretty much have to tune silently at gigs and they're good for setting intonation.