Infact, it is impossible to get at cheap rates than an international price, the lowest price you can buy would be no less than global price however there are a few countries like korea, nigeria where the prices are more higher than actual price, you can buy at normal price from usa and sell to koreans at higher price
you made some point here.
USA is good and cheap but not as cheap as Nigeria.
Nigeria is the cheapest and there are no laws to regulate how many you can buy a day. I own an ecurrency exchange company in Nigeria
www.nairaomm.com we have chinese clients. they buy from us and pay in our local currency before we send them btc based on how many we could get.
they get guaranteed 10 sometimes 20 sometimes 30 btc daily from us.
their country has some tax and number of amount you can send to and fro a bank account.
such restriction is not in Nigeria. as long as you have a current account or registered company act you can buy from any exchanger as you want and the crypto transaction is not being taxed.
its also cheap in Nigeria most times. many Nigeria sellers also use standard blockchain value for btc nothing like +5% or +10% etc.
if you will ask me i guess Nigeria then USA, Japan