Some mentioned SPSS, StatTransfer, they are not free. R and Python (also mentioned above) may be your choice. But personally, I would like to recommend Python, the syntax is much more intuitive than R. You can just use several command lines with Pandas in Python to read and export most of the commonly used data formats:
import pandas as pd
df = pd.read_stata('YourDataName.dta')
df.to_csv('YourDataName.csv')