If he is your friend then why not ask him about his method? I think the best way when It comes to the fees and the limits would be to trade with other individuals on the forum or LocalBitcoins. You just need someone/a few people who have a decent amount in stock so they could sell you regularly, this method is also better because you could cover multiple payment methods and that's not the case with the exchanges.
Well i have been seeing him doing that but he would not disclose the site. (simple business) as far as i know that website has no limits for buying.
In reference to Localbitcoins, they do have multiple payment methods but the rates are sky high when you compare it to a exchange price. That goes the same for paxful too.
whichever website i come across has very low limits to buy and one who has good price doesn't accepts payment from usa.