外國一些唔出名既職業網球員是靠甚麼搵食?

These professional players are referred as "journey man" meaning they travel on their own expense to enter tournaments to make a living.
Live of a journey man can be tough as he/she usually doesn't have much of any sponsorship. He/she has to pay their own travel cost, equipment and tournament fees. If a journey man is lucky on making into quarterfinal or better, he/she may earn decent prize from the wins. Otherwise, these players may not break even on the cost if they lose in the first round.