Though these can be perpetrated elsewhere, theybtend to be common in Manila at the moment.
1) "Hey! I think I know you from..." Often, it's someone who claims to work at your hotel, and coincidentally, it's their day off and they'd like nothing more than to offer to show younthe sughts - and lead you into a trap where you are robbed. It's hardly unknown elsewhere, but it's very common in Manila.
2) Calesas / kalesas - the horse drawn scam. It seems attractive to take a horse-drawn carriage in the historic areas, particularly Intramuros - and it is. But there are honest tours and rip-offs, so be careful. The scam begins when you are shilled, agree to a price, but stop on your trip when a man authoritatively steps in and displaces the driver - claiming the driver is inept and more importantly telling you the hire is much more - perhaps ten or more times what you agreed upon with the original driver. See
here for some ideas about hiring a
calesa. "As a rule, a Manila carriage ride costs PhP 300 for two people for 30 minutes. That’s $8 or £5." Extras and stops raise the rates, of course. (Some recommend you observe a bit and select a carriage with well kept looking motive power, aka horse.)
3) Taxis. Okay, this can be true anywhere, but some Manila taxi drivers are very aggressive. Assure the meter iscreset to zero and activated when you get into the taxi. Avoid taxi touts at MNL / NAIA International Airport, as they're likely pirates (soliciting by or for drivers at the airport is illegal).