If you’re a new guitar player then you’ll need to keep your guitar in tune.  You’ll usually get some accessories with your new guitar, sometimes that includes a tuner.  If you have one of those little pitch pipe looking things, I wouldn’t recommend using it.  If you’re a new guitar player you haven’t trained your ears enough, and they’re not always that accurate anyway.  Get yourself a tuner for acoustic guitar and you’ll be better off.  They’re pretty cheap, around $20 for a decent one and their easy to use.  There are different types out there, some are made for any instrument, and these will work fine on guitar, but if you don’t understand about key, pitch, scales, etc, it might be a little confusing for you to use one.  Look for a standard acoustic guitar tuner, these are made specifically for the strings on a guitar.  They have a little needle that points straight up when you’re in tune.  If they swing to the left, you’re flat (below pitch) and need to tighten your string.  If it swings to the right you’re sharp (above pitch) and need to loosen your string.  Here’s a list of some of the best acoustic guitar tuners from Musicians Friend. Now the Korg acoustic guitar tuner is one of the best selling, but it’s a matter of opinion, you don’t really need a super expensive one, just a standard acoustic guitar tuner will do.  You can get an acoustic guitar tuner clip, it clips onto your soundhole so that you can see what you’re doing while using your hands.  I don’t really think that’s necessary but you can if you want.