That's a rhetorical question right? In that case i would ask the nearest guy to blow him for a twenty (i consider that a fair price for a blowjob from a slightly prettyish girl), repeat the above process a few more times and boom i've got enough dough for both a few nights in a half decent motel and for a few meals a well. After that i'd see where the situation takes me but prostitution isn't an only solution...
Now if i were a guy in the same situation... i'd just suicide at that point...
Selling drugs and other crimes (like stealing) is also an option.
You can also beg for money. I once met a woman whose very demanding work required ~11h per day for a minimal wage (my country mw is really low); one day she met an ex co-worker asking for money on the train, and the ex-coworker said she would get more money through it than working, and it was less demanding and it required less time per day.
Tip: you can also use your first amount of money to get some candies and start selling them. My father said he once met a guy in the trains saying he planned to do exactly this by begging; the problem is that he was doing it for weeks straight.
And many countries have places dedicated for the less fortunate, both those provided by the government, and those provided by other things (including religious groups). You can make use of them.
In any case, it's wiser to have a plan before all that. Using the internet to get know more things and even making friends in other places is a good thing, specially if it's with people who were once in the same situation. Trying to get money from your home before going out is also not a bad thing to do, but you must be cautious for your parents to not call the cops saying that you stole things and even convincing them of stupid things like "you wanted to sell everything to buy drugs". Believe me, for I have experience in it: the mere fact of them being older than you makes it VERY easy for everyone to believe in any shit they say to make you look like a villain and they look like saints; and it's really everyone will believe them: police, teachers, religious authorities, doctors, therapists and so on.
Obvious, this is all for "normal" cases of needing such things. If you are like me who needs some specific meds (some of them expensive) and have other "high maintenance" things, suicide may be way easier to think of, no matter if you are a guy or a girl.