Wondering about ppl buying phones from uk and resell it here in algeria

Salam alaikom , hope u r doing great . I have heard that ppl buying phones from uk and resell it here in algeria and earn a lot ( rabi ybareklhm ) So i have qstn : How i can do it ? ( i don't have a ressource there ) Like the best delivery way and how much it costs ( i heard that the best is dhl )