When setting up the feed, make sure the currencies for both price and sale price include USD.
Also make sure that the setup in Google Merchant Center you choose United States with currency USD.
If you are in Turkey then most likely that is the issue.
Go to Google Merchant Center >Products > all products > click on a product > check that the prices are correct.
1) simply add your shipping details explained here: https://support.google.com/merchants/answer/6069284?hl=en
If you are using the free shopping app, make sure to disable automatic shipping settings.. Otherwise it will overwrite your Google Merchant Center settings.
2) Go to Google Analytics to see analytics data.