Price is same all over all currencies but there may be small % difference in price from one trading platform to another but if you are not doing arbitrage trading this difference doesn't matter a lot.

the prices are actually various in every exchanger sometime in x echanger is quite high but the margin is not too far compared with y exchanger but the market will be following each other,you need to analyze every exchanger and see the price margins but don't expect that much,and the price is depend on the exchanger not on the currencies,correct me if i'm wrong

I really depends o whic exchange to wherever in the world someone is using to change his btc to fiat. Let's just say maybe somewhere where rate of $ is low , there is also a possibility that bitcoin rate is lower compared to other because most exchange uses $ as a rate.

There is no such thing. What you wanna ask is arbitrage trading between the exchanges. 1 btc is ~630$, ~573€. Which one looks cheaper to you? € or $? If you collect your paychecks with €, $ is cheaper.

You could buy and sell between the currencies, if one currency strengthens against another, but the margin for arbitrage is so thin between these deviations that you will have to buy and sell significant amounts to make a decent profit. So you buy with € at a specific price and then sell for US Dollar, when the price dropped against the €. Is that what you want to do?

Yes theoretically but more so about learning about btc than trading margin

the only way to truly measure it. is in comparison to minimum wage and also price of buying groceries.

EG
california minimum wage is $10 so for 60 hours of labour ($600) you can get ~1btc
Idaho minimum wage is $7.25, so for 82 hours of labour ($600) you can get ~1btc

trying to think about only the $$ as is is futile. because in most cases buying with uk pound us based on the exchange rate via dollars.

but if you think of it from minimum wage (£7.20)
UK minimum wage is £7.20, so for 67 hours of labour ($489.52=$600) you can get ~1btc
which out of the 3 examples make it "cheaper" to buy bitcoin in california, then UK, then idaho

ill let you do the maths for REAL VALUE. for all area's.. and not the fiat value based on fiat exchange
its also worth adding in the 'cost of living' metric to get a more defined real "cheap" list of places to live to get bitcoin

EG
fiat:
california min wage= $10, loaf of bread $2
idaho min wage= $7.25, loaf of bread $1.50

now imagine they asked each other for one hours labour.
Idaho gets $10 from cali' and can then buy 6.66 loaves.. = happy
cali' gets $7.25 from idaho and can only buy 3.625 loaves = not happy

btc:
california min wage= 0.01666666btc, loaf of bread 0.003btc
idaho min wage= 0.01208333btc, loaf of bread 0.0025btc

now imagine they asked each other for one hours labour.
Idaho gets 0.01666666btc from cali' and can then buy 6.66 loaves.. = happy
cali' gets 0.01208333btc from idaho and can only buy 3.625 loaves = not happy

it doesn't mean that but it is still possible.
it is not that profitable that you may think because the market balances out itself in a very short time and also because there are fees involved but there is always times that there is a bigger difference so balancing out takes time.

Franky, I think he is referring to different currencies, not a single currency. In the USA a dollar is a dollar.. no matter where you spend it,

you will get the same amount of Bitcoin for it, no matter where you are. { If you are in California or Idaho, and you buy at exactly the

same exchange, you would get the same amount of bitcoins. } He wants to buy Bitcoin with the cheapest currency. Try the Zimbabwian

dollar. { Just joking...  you will still get the same amount, no matter what currency you use. } 

As I know bitcoin has the same price in every kind of currency. In my currency (rub) 1 bitcoin cost like 40000 rub and in dollar 600$. And 600$ Cost as 40000 rub. So there is no difference.