1 An oil change typically costs $20-$55, depending on whether the work is performed at an independent shop, an oil-change retail chain or a dealership, and the number of quarts of oil used in the vehicle. Oil changes involve more parts than just the oil itself. 2  Included in the cost of any oil change is the cost of labor, the oil, shop supplies, an oil filter and any associated gasket, O-rings or seals, plus the cost of disposing of the used oil. 3  Labor is not charged in the same way that is for other repair jobs.
Trade surplus is defined as that a nation is exporting more than it imports, giving it an inflow of currency. An example of trade surplus is that China is exporting more goods than China imports from other countries. YourDictionary definition and usage example.
Of course they matter. Trade deficits arise when we import more than we export. Easy said. It's a tad bit more complicated. When we keep incurring these deficits, year after year, we use our domestic currency (the $) to pay for those imports. This results in our trade partners getting a considerable supply of those $.