one thing SDbigdogg88 forgot to include is to never, ever, ever give money to one of the poor kids begging for money.
Your heart will break when the poor bastard looks at you with sad puppy eyes, but resist the temptation. Once you give one kid money, no matter how little it is, 10 more kids will come out of nowhere and ask for more and will follow you for half a block.
Also the girls from the alley are cheaper yes, but you get what you pay for. Generally is one position only, if you want her toppless she'll ask for more $, and hairy pies (well taht may be a plus for you, but i like it trimmed hehehe).
also most of them will not do anything but lay there, and most won't get one top.
... at least taht was my experience
i hope you guys have a good time, im myself im going down there this monday