All forex rates are comprised of a couple of prices - the bid price and the ask price. The difference between the two is called 'spread'. The ask price is always higher than the bid price.
Don't forget that when you buy a currency, you buy it at the ask price, and when you sell, you sell at the bid price. Put in simpler terms, you always buy or sell at the more disadvantageous price of the two; that is, disadvantageous for you, not for your broker.
When you take a trade, your position will start out as a negative number (a loss) until you make up the spread.