Update : It appears the only people getting the 20 Farm Cash are actually ones who were charged for their free dart.
Farmers were getting a Free Mystery Dart and they were in fact charged 20 Farm Cash for popping a balloon. Tonight Farmville rectified this by giving farmers 20 Farm Cash.
Here is a look of tomorrow's market screen, zynga will be updating farmville this night! so guys keep an eye on market to catch the items, before the others do!
You can see All prices in these screenshots!