its high risk if we didn't follow news, market prices and analytics.. in a day on my country, bitcoin rate can fluctuative until 100 USD 
What country are you in and what are you talking about? You should have pretty close rate to online, you can use a exchange to get that rate.
If you are saying in your country you meet up and get less... you are doing trading wrong. In person should always be more then exchange.
If you could explain your statement a little more, I'm not sure I got it 100 percent.