How much is 三百文钱 today? I'm going over this sentence here:


  剃头匠不愿招惹麻烦，只得赔偿三百文钱。


I'm curious to know how much 三百文钱 would be worth today.

汉语大辞典 has an entry for 文钱 but all it says is:


  钱。因钱有文字，故称。


How much was 300 wen worth during the Ming Dynasty?
This should be a question for history not Chinese language.


For the language part: 
In ancient China, multiple kinds of currency are used like gold, silver, copper coin and even cloth. 文 is the unit for copper coin like this Ming dynasty coinage
For the history part:
During Ming dynasty, 1000 文 ≈ 1 两 silver which can buy 2 石 rice = 188.8 kilogram rice = 416.2 pound rice. So 300 文 is about 124.9 pound rice.