The fastest and easiest way to fine tune your guitar is to use an electronic guitar tuner. Of cause you may use a downloaded app in your smart phone to do that, but it may not work well in a public or noisy area. Further more some apps have not been verified on its accuracy, we can’t judge whether is correct or not. The size of a smart phone is still much more bigger than an electronic tuner, it is not easy to put as close as to your guitar during tuning.
A portable clip-on tuner is more likely to be more convenient and accurate as they are factory calibrated, closer to your guitar as it will be clipped on the headstock, easy to view indicator which is good during tuning.
Price is always a final concern when come to a buying stage. Here I have done a review on two lowest price brands which can be bought at amazon. Both are fine for home and personal use and price are pretty close to each other.
Mugig T-1 versus Getaria AT-101
Getaria AT-101 seems to have a pretty good five stars review from their users than Mugig T-1, but I found that its specification is uncleared as compared to Mugig. First, it doesn’t state the detection mode it has, either by sound, by vibration or both, and not sure whether got Auto-Power-Off function.
Since both are just different by a few dime, so is up to the buyer to decide.