The tuner is an extremely useful device that can help you adjust your strings to the most accurate pitch possible if you cannot determine the proper pitch by ear. There are many free tuning apps available to download on your phone. However, without a microphone, this may not be the most effective option. For a thorough, precise tuning. However, there are still inexpensive options, such as the Snark SN5X Violin Clip On Tuner. Look for an option that best suits you.