There is some serious confusion here.
When you “buy” a currency pair on the forex market, [B]you are not really buying anything.[/B] You are entering into an agreement to buy something later. “Later”, in the forex market, means two days from the time you execute your trade.
Your broker requires that you post a good-faith deposit — called margin — at the time that you execute your trade. Many brokers (including my broker, FXCM) base this margin amount on the number of units of base currency in your trade, regardless of the market price of the pair you are trading.
As an example, let’s say that you trade through one of these brokers, and let’s say that you buy 10,000 units (1 mini-lot) of the GBP/USD. Your broker will require the same margin whether the GBP/USD is priced at 1.5000, or 2.5000, or 10.5000.
[B]Therefore, when you execute your trade, you don’t care how high (or low) the price is; you only care about which direction the price is going from here.[/B]
When a trader refers to the “high price” of a currency pair, he is not thinking of the high cost of buying that pair; he is thinking of the probability that the price will decline from that “high” level. A decline will cost him money.
If I knew that the GBP/USD was headed higher from here, I wouldn’t care how high its current price is. Whether it’s 1.5000, or 2.5000, or some other price, it will “cost” me the same 100 USD in margin to trade 1 mini-lot of GBP/USD.
[B]Therefore, only one thing is important to me: that the price is higher when I sell, than it was when I bought. [/B]
If the price increases from 1.5000 to 1.5100, I make 100 pips. If the price increases from 2.5000 to 2.5100, I make 100 pips.
Either way, it’s the same cost (margin) to transact business, and it’s the same profit.
[B]The “purchase price” of the GBP/USD (that is, the dollar-cost of the British pound) is of no concern to me.[/B]
I hope that helps you.