Two prices, always
Look at any quote and you will see two numbers. The bid is the price the market will buy from you at — what you get when you sell. The ask (or offer) is the price the market will sell to you at — what you pay when you buy. The ask is always the higher of the two.
The spread is your first cost
The gap between them is the spread, and it is the cost of every trade before anything else happens. If EURUSD is 1.08500 / 1.08512, the spread is 1.2 pips. Buy at 1.08512 and the price has to rise 1.2 pips before you are back to break-even.
spread = ask − bid
Why it changes
- Liquidity. Majors during the London and New York overlap have the tightest spreads; the same pair at 4 a.m. Sydney time is wider.
- News. In the seconds around a major release, liquidity providers pull back and spreads widen sharply.
- Account type. A Standard account quotes a slightly wider spread with no commission; an ECN account quotes the raw spread and charges a commission per lot instead. See the account comparison.
Summary
You buy at the ask, sell at the bid, and the difference is the spread — a cost you pay on every trade, which is lowest in liquid pairs during busy hours.