My 9th times great-grandfather arrived in Philadelphia in 1750 aboard The Phoenix at around 19 or 20 years old. He was not an indentured servant, had the means to pay the 7 1/2 pounds fee and signed his own name to an oath of allegiance to King George II, rather than marking an X. Apparently, he came from the Koblenz area of modern Germany. What factors would have led a young, literate man to immigrate at that time?
Well at the time around 1740-1760 there were quite some tensions in Germany since Prussia and Austria were nearly constantley at war in the three "Schlesische Kriege". So maybe the high tension in Germany motivated him to go to America. On the other side moving to America was also interesting for a young man because you could visit the world and inhabitate a chunk of american land without having to pay as much as in feudal Germany.