if you can buy from your friends with cheap price of btc then its good but i don't think you can found cheap price because the price is follow with the market price. but maybe there is a different between one market into other market and its normal as long as the different is not big, so you can not buy with more cheap than the price of the market rate, no matter how much you bought bitcoin amount. but you should thinking about the fee because the fee is the important factor that help you to get fast confirmation so you can predict how long the bitcoin can arrive in your wallet from beginning you bought bitcoin.