If the problem is just 'dirty money' then it is not a big problem. There has been a lot of crypto exchange so as each person only has to choose it according to their own desires, but it is highly recommended for newcomers to buy bitcoin or altcoin on the local exchange, I guess every country already has it. I think the most complex problem for someone who wants to buy bitcoin is a legality of each country, they will find out in advance the response of their government to bitcoin, this will determine everyone to buy.